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blocks.js
Blocks.js is a view library - a set of extensible web components for building visual user interfaces and styling web applications in pure-javascript. Modular, composable web components. Modular, composable styles.
The power of functions and variables is unparalleled, and yet languages like HTML and CSS, which don't have any ability to compose structures together, are still the primary ways people build web applications. Framework after framework has come along to try and solve the problem of making web pages dynamic. Angular, Backbone, Ember, jQuery, mooTools, Dojo, YUI, etc have all tried to be everything to everyone. But what they fail at providing is simplicity and modularity. They end up with bloated libraries filled with features you're not using.
Blocks.js is here to change that. Finally, modern application development for the browser!
blocks.js
?blocks.js
is notvar Button = require("blocks.js/Button")
var Style = require("blocks.js/Style")
var Container = require("blocks.js/Container")
var list = Container()
;[1,2,3].forEach(function(n) {
var text = "Hi "+n
var toggleButton = Button(text) // create a button
// make it do stuff when you click on it
toggleButton.on('click', function() {
if(toggleButton.text !== "RAWRR!!!") {
toggleButton.text = "RAWRR!!!"
toggleButton.state.set('color', 'rgb(128, 0, 0)')
} else {
toggleButton.text = text
toggleButton.state.set('color', 'black')
}
})
// add the button to the list
list.add(toggleButton)
})
var greet = Button("send", "Send your Greetings") // labels like 'send' can differentiate otherwise identical types of blocks
list.add(greet)
// create styles with style objects ..
list.style = Style({
border: '1px solid blue', // .. that use familiar css values,
marginRight: 34, // .. camelCase css properties and integers interpreted as "px" values when appropriate,
Button: { // .. sub-block styles,
$$firstChild: { // .. pseudo-class styles,
color: 'rgb(0,100,240)',
},
$state: function(state) { // .. more sophisticated styling techniques
return Style({
color: state.color
})
}
},
$send: { // .. style based on an object's label, and ..
color: 'green'
}
})
// append the list of buttons to the document body (so it shows up)
list.attach()
// custom blocks (use your favorite javascript class library - here proto is being used)
var NameInput = proto(Block, function() { // inherit from Block
this.name = 'NameInput'
this.build = function(LabelText) { // the `build` method initializes the custom Block
this.nameField = TextField()
this.add(Text(LabelText), this.nameField)
this.nameField.on('change', function() {
list.children[0].text = "Hi "+this.val
})
}
})
var nameInput = NameInput("Your Name: ")
greet.on('click', function() {
var text = Text("Whats up, "+nameInput.nameField.val+'?')
text.style = Style({display:'block'})
text.attach()
})
nameInput.attach()
If anything in the documentation is unclear, or you want to see more examples, the unit tests give a comprehensive and exhaustive set of examples to look at.
blocks.js
?Block
objects) and Style
objectsblocks.js
, you write in 100% javascript. The only html requirement is a document
body
. You can still add plain old HTML into your blocks using block.domNode.innerHTML
tho if you so choose.Blocks
can be added as a child to any standard dom object and they can be styled with standard css stylesheets if you so choose.Blocks
give you direct access to their domNode
so you can use the dom manipulation libraries you're used to.$state
, $setup
, and $kill
javascript in your Style
objects, you can include any javascript that is stylistic rather than structural.Block
modules with real APIs that anyone can release online. HTML snippets are so 1995.blocks.js
works in modern browsers without polyfills.npm install blocks.js
or download the built package blocks.umd.js
from the 'dist' folder in the repository
var blocks = require('blocks.js') // node.js and webpack
define(['blocks.umd.js'], function(blocks) { ... } // amd
<script src="blocks.umd.js"></script>
<script>
blocks; // global 'blocks' module object
</script>
Block
All blocks inherit from Block
- the basic building-block of the system. Blocks are EventEmitters, and emitting events is one of the primary ways blocks should communicate.
Block
is abstract and can't be instantiated on its own. See the section ''Custom Blocks'' for details on how to create objects that inherit from Block.
var Block = require("blocks.js") // or
var Block = require("blocks.js/Block") // or
blocks.Block // if you're using the umd package
Block.name
- The name of the Block. Used both for naming dom elements for view in browser dev tools and for styling.
Block.attach(listOfBlocks)
- Appends the passed blocks to document.body
. IMPORTANT: only attach a block to the dom via
this attach
function or a block's attach
method. Without this, styles won't be rendered.
Block.attach(domNode, listOfBlocks)
- Appends the passed blocks to the passed domNode
.
Block.detach(listOfBlocks)
- Removes the passed blocks from their respective dom parents.
Block.createBody(callback)
- Dynamically creates the body tag. Calls callback
when done.
block.parent
- The Block's parent (which will also be a Block)
block.children
- An array of the Block's children (which will all be Blocks themselves).
block.domNode
- The Block's standard dom node object.
block.label
- A string used for styling. Should be set once when the object is instantiated, and cannot change. See the section on Style
objects for details about how this is used.
block.excludeDomEvents
- A set of dom events to exclude from automatic registration. Will have the structure {eventName1:1, eventName2:1, ...}
. See the documentation for on
for more details.
block.state
- An observer object that can be listened on for changes. Can be used for any purpose, but is intended for being used to create dynamically changing styles. See the section on Style
objects for an example.
block.add(block, block, ...)
- Appends blocks as children to the calling block. This causes the domNodes of the passed blocks to be appended to the calling block's dom node.
block.add(listOfBlocks)
- Same as above, but listOfBlocks
is an array of Block
objects.
block.addAt(index, block, block, ...)
- Adds blocks as children to the calling block at a particular index.
block.addAt(index, listOfBlocks)
- Same as above, but listOfBlocks
is an array of Block
objects.
block.addBefore(beforeChild, block, block, ...)
- Adds blocks as children to the calling block before a particular child. If beforeChild
is undefined, this will append the given nodes.
block.addBefore(beforeChild, listOfBlocks)
- Same as above, but listOfBlocks
is an array of Block
objects.
block.remove(block, block, ...)
- Removes the passed blocks as children.
block.remove(listOfBlocks)
- Same as above, but listOfBlocks
is an array of Block
objects.
block.remove(index, index, ...)
- Removes, as children, the blocks at the given index
es in the children
list.
block.remove(listOfIndexes)
- Same as above, but listOfIndexes
is an array of indexes to remove.
block.attach(domNode=document.body)
- Appends this Block
's domNode to the passed domNode (default document.body
).
IMPORTANT: only attach a block to the dom via this attach
function or a block's attach
method. Without this, styles won't be rendered.
block.detach()
- Removes this Block
's domNode from its dom parent.
block.attr(attributeName)
- Return the value of the attribute named attributeName
on the Block's domNode.
block.attr(attributeName, value)
- Sets the attribute to the passed value
.
block.attr(attributeObject)
- Sets the attributes in the attributeObject
, where attributeObject
looks like: {attribute1: value1, attribute2: value2, ...}
.
block.style
- Holds the object's Style
object. Starts out undefined
, and can be set to undefined
to remove a Style
that has been set. Changing this property triggers style affects in the Block's children.
block.visible
- Setting this variable to false hides the block using "display: none;". Setting this variable to true unhides it. Accessing the variable will return its visibility state.
block.focus
- Setting this variable to true gives the block focus on the page. Setting this variable to false blur
s it. Accessing the variable returns whether or not the block is the focused element on the page.
block.selectionRange
- Returns an array representing the selection range in terms of visible character offsets. E.g. a value of [2,4]
means that the current element has 2 visible entities (usually characters) selected within it at offset 2 and 4 from the start. Note that if there are hidden characters like multiple spaces in a row, or newlines, or other non-visible characters (mostly only applies to contenteditable nodes), they are ignored.
block.selectionRange = [offsetStart, offsetEnd]
- Setting the selectionRange
property sets the selection inside the Block's domNode based on the given offsets.
Example of selectionRange
:
var x = Text("You're not my buddy, guy")
x.attach()
x.selectionRange = [0,6] // selects "You're"
EventEmitter
All methods and properties from EventEmitter
are inherited by Block
. The important ones:
block.emit(event, data, data2, ...)
- Emits an event that triggers handlers setup via the Block's on
methods.
block.on(event, callback)
- Registers a callback
that will be called when the passed event
is emit
ted by the Block.
event
- The string event name to listen for. If the passed event is one of the many standard dom events (e.g. 'click', 'mouseover', 'touchstart', etc), the passed handler will be registered as a dom event handler in one of three cases:
excludeDomEvents
object is undefinedin
the block's excludeDomEvents
propertycallback(data, data2, ...)
- the callback gets any arguments passed to emit
after the event name.block.once(event, callback)
- Like on
but the callback
will only be called the first time the event happens.
block.off(event, callback)
- Removes a callback as an event handler (the callback
won't be called for that event again).
block.removeListener(event,callback)
- Same as off
.
this.removeAllListeners(event)
- Removes all the callbacks for the passed event
.
this.removeAllListeners()
- Removes all callbacks.
ifon
The ifon
and related methods are useful primarily for performance reasons. They allow registering event listeners only when they're needed, so that the browser doesn't get overloaded with event handlers. Its recommended that ifon
is used whenever possible. An example:
var text = Text("CLICK ME")
var parent = Container(text)
var handler;
parent.ifon('someoneClickedTheThing', function() {
text.on('click', handler = function() {
parent.emit('someoneClickedTheThing', "I can't believe it")
})
})
parent.ifoff('someoneClickedTheThing', function() {
text.off('click', handler)
})
block.ifon(event, callback)
- Registers a callback that will be called when a handler is registered for event
if it had no handler registered previously. If there is already a listener attached to that event, callback
is called immediately.
callback(event)
- The callback gets the newly registered event type as its argument.block.ifoff(event, callback)
- Registers a callback that will be called when the last handler for event
is unregistered.
block.ifoff(callback)
- Registers a callback that will be called when the last handler for any event is unregistered.
callback(event)
- The callback gets the unregistered event type as its argument.block.removeIfon()
- Removes all ifon
handlers.
block.removeIfon(event)
- Removes all ifon
handlers for the passed event
.
block.removeIfon(callback)
- Removes callback
as an "all" ifon
handler (a callback passed to ifon
without an event).
block.removeIfon(event, callback)
- Removes callback
as an ifon
handler for the passed event
.
block.removeIfoff()
- Removes all ifoff
handlers.
block.removeIfoff(event)
- Removes all ifoff
handlers for the passed event
.
block.removeIfoff(callback)
- Removes callback
as an "all" ifoff
handler (a callback passed to ifoff
without an event).
block.removeIfoff(event, callback)
- Removes callback
as an ifoff
handler for the passed event
.
proxy
The proxy
method uses ifon
and ifoff
to minmize the number of event listeners that need to be attached in the system.
block.proxy(emitter, options)
- Proxies event registration to emitter
.
emitter
- The emitter (usually a Block
) to proxy handler binding tooptions
- An object that defines what events are proxied. If undefined
, all events are proxied. The object can have one of the following properties:
only
- An array of events to proxy.except
- An array of events to not proxy. All other events are proxied.Example of proxy
:
var A = Text()
var B = Text()
A.proxy(B)
A.on("click", function() {
console.log("hey hey heyyy! "+3)
})
B.emit("click", "Ughh..") // console prints "hey hey heyyy! Ughh.."
"newParent"
- Emitted when a Block gets a new parent. Note: this event is used by Style
objects, so don't prevent these events.
"parentRemoved"
- Emitted when a Block is detached from its parent. Note: this event is used by Style
objects, so don't prevent these events.
Block
object will emit any standard dom event ("click"
, "mousedown"
, "keypress"
, etc) when listened on. Note that a Block
doesn't add an event listener to the dom node until someone listens on
that event on the block. This minimizes the number of event listeners that are registered on the page. To see the list of dom events this applies to (supposed to be all of them), see the top of src/node_modules/Block.js
Blocks.js is all about custom blocks. That's the point: your application should be built as a composition of custom blocks on top of custom blocks so that, instead of a million divs, you have semantically appropriate javascript web components.
In this documentation, we're going to be using the class library proto. The descriptions here apply to both inheriting from Block
and inheriting from any of the standard blocks. There are a couple special properties to create when making a custom Block
:
name
- The name is a required property, should be named whatever your class is named, and should be a somewhat unique name in your system (tho it isn't required to be unique).build()
- The "sub-constructor". The constructor calls this method, passing all arguments, to the build
method. The return value of build
is ignored.defaultStyle
- If set to a Style
object, the style object will be the block's default style. Unlike explicitly set Styles and inherited Styles, css properties in defaultStyle
do cascade line-by-line. Also, if a block inherits from another Block
class that also has a defaultStyle
, the default styles mix together with the child Block
class style properties overriding the parent Block
class's default properties. So in the below example, if block
is given a style that defines color: green
, it's fontWeight will still be 'bold'.For example:
var CustomBlock = proto(Block, function() {
this.name = "CustomBlock"
this.defaultStyle = Style({
color: 'red',
fontWeight: 'bold'
})
this.build = function(x) {
this.x = x
}
})
var block = CustomBlock(5) // block.x is 5
If you'd like to release a custom Block
or set of Block
objects, there are a couple of important things to remember to do:
blocks.js
as a normal "dependency". Instead, it should be added as a "peerDependency" or perhaps a "devDependency". It shouldn't be a normal "dependency" because otherwise bundlers may bundle multiple copies of blocks.js when using your custom block module (even though bundlers like webpack dedupe files, if the versions of webpack being used are slightly different, they would still package together both versions of blocks.js)<script>
tag, do not bundle blocks.js in your distribution bundle. It should assume the blocks
global variable (e.g. blocks.Block
) is available.proto
If you're building Blocks with something other than proto
(or are using a version of proto older than 1.0.17), note that blocks.js relies on the following properties:
proto
sets this automatically, it is not a standard property and if you're using a different library from proto, you must set this manually.proto
sets this appropriately, most class libraries probably don't and it isn't simple to manually set. See here for details.Also, make sure that Block
's constructor is called on new instances that inherit from Block
.
Properly subclassing a prototype in javascript isn't the simplest thing to do, but if you want to do it, here's how:
var CustomBlock = function() {
Block.init.call(this) // Block's constructor must be called
}
CustomBlock.parent = Block // needed for correct Style rendering
var Intermediate = function(){}; Intermediate.prototype = Block.prototype
CustomBlock.prototype = new Intermediate()
CustomBlock.prototype.name = 'CustomBlock' // the name is a required property
CustomBlock.prototype.constructor = CustomBlock // required for correct Style rendering, and is a standard javascript convention
CustomBlock.prototype.build = function(constructorArgument1, constructorArgument2, ...) {
// .. custom constructor code
}
CustomBlock.prototype.customMethod = function() {
// ...
}
The built-in standard blocks all inherit from Block
and so have all the methods and properties in the above documentation. For each build-in block, its name
property will be the same as the name the documentation uses for it. For example Button
will have the name "Button"
.
To use these built in blocks, access them via either require("blocks.js/<BlockName>")
or blocks.<BlockName>
. For example:
var Table = require("blocks.js/Table") // webpack or browserify
// or
var Table = blocks.Table // if loading the umd bundle in a <script> tag
There are some conventions that can help you learn to use standard Blocks, and help make custom Blocks you build more easily understood. These conventional properties, constructor parameters, and behavior are encouraged to be used in custom Blocks built by you, especially if you're planning on open-sourcing them.
Every standard Block has an optional first parameter label
.
This makes it easy and non-intrusive to label parts of your custom Blocks for easy styling.
In as many cases as possible, Blocks will use properties defined with getters and setters rather than using methods. There are a few standard properties that some blocks have:
text
- Gets and sets some visual text that a Block has. Button
, Text
, and Select.Option
have this property.selected
- Gets and sets the selected-state of the Block. CheckBox
, Select.Option
, and Radio.Button
have this property.val
- Gets and sets some value that a block has. This will never be the same as either text
or selected
. Radio
, Select
, TextArea
, and TextField
all have this property.This is a standard event that many blocks can emit:
change
- Emitted when an important value of a block changes. This will always be either the block's val
property or its selected
property (but never both). Change events won't have any information passed with them - you can access the object itself if you need data from it.Some blocks have sub-blocks specifically related to them. For example, Select
has Option
blocks, and Table
has Row
and Header
blocks, and Row
and Header
have Cell
blocks respectively.
Select
has an options
map.Select
or Table
) to create a new sub-block (e.g. Option or Row), append it to the calling block, and returns that sub-block. The method will be named the same as the sub-block but in lower-case (e.g. selectBlock.option(...) will return an Option block).Your standard html <button>
.
Button(text)
- Returns a new button that has the passed text.
Button(label, text)
button.text
- Sets or gets the button's text.
Your standard html <canvas>
.
Canvas(height, width)
- Returns a new Canvas object that has the passed dimensions.
Canvas(label, height, width)
canvas.height
- Sets and gets the canvas's height.
canvas.width
- Sets and gets the canvas's width.
canvas.context(type, attributes)
- Returns a standard canvas context. The type
and attribute
parameters and return value are the same as the html-standard getContext
.
canvas.toImg
- Returns a data-url representing the image currently drawn on the canvas.
canvas.toDataURL
- Same as canvas.toImg
.
Your standard html <input type="checkbox">
.
CheckBox()
- Returns a new unchecked CheckBox.
CheckBox(label)
checkbox.selected
- Sets and gets the checkbox's selected state (true for selected, false for unselected).
A <div>
that contains other blocks.
Container(block, block, ...)
- Returns a new container with all the passed blocks as children (in the passed order).
Container(listOfBlocks)
- Same as above except listOfBlocks
is an array of blocks.
Container(label, block, block, ...)
Container(label, listOfBlocks)
Your standard html <img>
.
Image()
- Returns a new empty image.
Image(imageSource)
- Returns a new image with the passed imageSource
.
Image(label, imageSource)
image.src
- Gets or changes the image's source.
An <ol>
or <ul>
element.
List()
- Returns a new empty list.
List(ordered)
- Returns a new empty list. Is an ordered-list if ordered
is true, and an unorderd-list otherwise.
List(listInit)
- Returns a new populated list. listInit
is an array containing either Block
objects or strings to add as list items.
List(ordered, listInit)
List(label)
List(label, ordered)
List(label, listInit)
List(label, ordered, listInit)
list.item(contents)
- Creates a new ListItem
with the passed contents
and appends it to the list, which can either be a Block
or a string.
list.item(label, contents)
List.Item
- The ListItem
class.
List.Item(contents)
- same as list.item
above, except doesn't append the item to any list.
List.Item(label, contents)
Block
A set of radio buttons. Radio
itself is not a Block
, but rather contains a set of related RadioButton
s (which are Block
objects).
Radio()
- Returns a new Radio
object where a button is not required to be set (same as Radio(false)
).
Radio(required)
- Returns a new Radio
object. If required
is true, a radio button will always be selected (and buttons cannot be deselected), otherwise radio-buttons can be deselected, and no radio button is selected by default.
radio.button(value)
- Creates a new RadioButton
with the passed string value
that is a member of the Radio
object.
radio.button(label, value)
radio.selected
- Returns the RadioButton
object that is selected.
radio.val
- Gets the value of the RadioButton
that's selected, or selects the RadioButton
that has the set value (e.g. radio.val = 'elvis'
would select the radio button with the value "elvis")
radio.remove(radioButton, radioButton, ...)
- Removes the passed radio buttons from the Radio
object's set. Note that this will not remove the buttons from the page - that must be done separately for whatever Block
contains the RadioButton
s.
radio.remove(arrayOfRadioButtons)
- Same as above, except the argument is an array of the RadioButtons
to remove.
radio.remove(value, value, ...)
- Removes the radio buttons that have the passed values from the Radio
object's set.
radio.remove(arrayOfValues)
- Same as above, except the argument is an array of the values who's radio buttons should be removed.
Radio.Button
- The RadioButton
class.
radioButton.val
- Gets or sets the value of the radio button.
radioButton.selected
- Gets whether the radio button is selected or not. If set to true, selects the button. If set to false, deselects it.
radioButton.selectNext()
- Sets the next radio button in the Radio
object's set.
radioButton.selectPrevious()
- Sets the previous radio button in the Radio
object's set.
Your standard <select>
element.
Select()
- Returns a new empty selection list.
Select(selections)
- Returns a new populated selection list.
Select(label, selections)
selections
- An object with the structure {optionValue: optionText, ...}
select.option(value, text)
- Creates a new Option
with the passed value
and text
, and appends it to the list.
select.option(label, value, text)
select.val
- Gets the value of the selected Option
, or selects the Option
with the set value (e.g. select.val = 'moo'
selects the Option
with the value 'moo').
Select.Option
- The Option
class.
Select.Option(value, text)
- same as select.option
above, except doesn't append the Option
to any list.
Select.Option(label, contents)
option.selected
- Gets or sets the selected state of the Option
.
option.text
- Gets or sets the display text of the Option
.
option.val
- Gets or sets the string value of the Option
.
Your standard <table>
element.
Table()
- Returns a new empty table.
Table(tableInit)
- Returns a new populated table.
Table(label,tableInit)
tableInit
- A list where each element in the list represents a row. Each element itself should be a list where each element is a Block
or string to put in a table Cell
. E.g. Table([['a','b','c'],[Text('x'),Text('y')]])
is a table with two rows and three columns, where there are only two cells in the second row.table.row(rowInit)
- Creates a new table TableRow
(<tr>
), and appends it to the table.
table.row(label, rowInit)
table.header(rowInit)
- Creates a new table TableHeader
(<th>
), and appends it to the table.
table.header(label, rowInit)
rowInit
- A list where each element is a Block
or string to put in a table TableCell
. E.g. table.row(['a','b','c'])
is a row with three cells.Table.Row
- The TableRow
class.
Table.Header
- The TableHeader
class.
Table.TableCell
- The TableCell
class.
Table.Row(rowInit)
- same as table.row
above, except doesn't append the TableRow
to any table.
Table.Row(label, rowInit)
Table.Header(rowInit)
- same as table.header
above, except doesn't append the TableHeader
to any table.
Table.Header(label, rowInit)
row.cell(contents)
- Creates a new table TableCell
(<td>
) and appends it to the TableRow
.
row.cell(label, contents)
header.cell(contents)
- Creates a new table TableCell
(<td>
) and appends it to the TableHeader
.
header.cell(label, contents)
contents
- Either a string (text content) or any value you could pass into block.add
(a Block, a list of Blocks, etc).Table.Cell(contents)
- Same as row.cell
, but doesn't append the cell to any row.
Table.Cell(label, contents)
cell.colspan(columns)
- Sets the column-span (colspan
attribute) of the cell.
A <div>
with text in it.
Text()
- Returns an empty Text object.
Text(text)
- Returns a Text object populated with the passed string text
.
Text(label, text)
text.text
- Sets or gets the object's text.
A multi-line text input field. Your standard <textarea>
element.
TextArea()
- Returns an empty TextArea.
TextArea(label)
textArea.val
- Gets or sets the testArea's value (the text inside the text box).
A one-line text input field. Your standard <input type='text'>
element.
TextField()
- Returns an empty TextField.
TextField(password)
- Returns an empty TextField with the password
attribute, meaning any text inside the box will be displayed so that only the number of characters can be seen, and not the characters themselves.
TextField(label, password)
textField.val
- Gets or sets the textField's value (the text inside the text box).
Style
objectsIf you're going to build a web application, why not do it with Style
?
While a Block
is pretty analogous to its HTML node, Style
objects in blocks.js are quite different from normal CSS.
In blocks.js, individual css style properties do not cascade. Instead, whole Style
objects cascade. This may not seem like much of a difference, but it makes all the difference. For example:
var parentContainer = Container([
Text('a'),
Container([
Text('b'),
Text('c')
]),
List([Text('d')])
])
c.style = Style({
Text: { // 1
color: 'blue',
fontWeight: 'bold'
},
Container: {
Text: { // 2
color: 'red'
}
}
})
In the above example, "a" will be bold and blue, and "b" and "c" will be red. But "b" and "c" won't be bold - that property does not cascade. The Text
styling inside Container
is isolated from all previous stylings of Text
, which means you don't have to worry about the styles someone used for elements further up the dom tree. I mentioned, tho, that whole Style
objects do cascade, and that is why "d" will also be blue and bold even though it isn't a direct child of parentContainer
.
Another difference is that blocks.js doesn't have selectors that can style any element on the page.
Traditional CSS stylesheets are developed by selecting a group of elements from the entire page
(via ids, classes, attributes, pseudoclasses representing element state, etc) and appending styles to them.
These styles may overwrite styles written earlier, and they themselves may be overwritten.
In blocks.js, Style
objects can only be attached in a strict hierarchical setting, where only a specific section
of the dom can be affected. In the above example, the Text
style marked 2 doesn't affect anything outside that inner Container.
For example, even though the text "d" is a Text
object inside a Container
object, it is not colored red.
That's because styles in blocks.js are not like the selectors you're used to from css.
They are strictly hierarchical - they only affect descendant Block
objects' (children, grandchildren, etc) from the point in
the dom they match.
The combination of the fact that blocks.js Style
objects only cascade as a whole object and that styles are defined hierarchically makes styles modular and provides isolation from other styles on the page, so that it becomes much easier to understand and manage styling for a page or entire application.
Style
constructorStyle(styleDefinition)
- Creates a Style
object.
styleDefinition
is an object where key-value pairs can be either style properties or selectors:
<cssPropertyName>
: the value is a valid css value for that style property.$setup
: the value is a function to be run on a block when the style is applied to it$kill
: the value is a function to be run on a block when a style is removed from it$state
: the value is a function to be run when block.state
changes (ie when its change
event fires).Style
object or a nested styleDefinition
object
<BlockName>
$<label>
$$<pseudoclass>
$inherit
<cssPropertyName>
This type of key-value pair is simple - just your basic css style. Example:
Style({
color: 'rgb(100, 200, 50)',
marginRight: 3
}
The above style would give a color and margin-right to whatever Block
is set with that style (block.style = styleObject
). Note that camelCase names can be used, and numbers are automatically appended with "px" if appropriate for the property (just like with jquery's css
method).
$setup
and $kill
$setup(block)
is a function that is run when the style is applied to a block, and $kill(block, setupObject)
is run when the style is removed from a block. Both functions get the block being given the style as their first argument, the $kill
also gets the return value of the $setup
function as its second argument. For example:
var S = Style({
$setup: function(block) {
block.text = "I got zee style"
return 20
},
$kill: function(block,setupValue) {
block.text = "I'm "+setupValue+"% less cool"
}
})
var t = Text("x")
t.style = S
t.text === "I got zee style"
t.style = undefined
t.text === "I'm 20% less cool"
$state
$state(state)
is a function that is run when the block's state
observer property emits a change
event (which happens when
its changed with its methods set
, push
, splice
, or append
). The state
function is passed the value of block.state.subject
as its parameter. The return value of the function should be a Style
object to mix with the object's current style.
Note that if you create styles in $state functions, remember that you will create a new style every time the state changes. This may be a problem with some applications that have a lot of state changes, or particularly rapid state changes (its unclear at what point this could cause problems).
Example:
var c = Text("hi")
var colorStyles = {
yellow: Style({backgroundColor: 'yellow'}),
red: Style({backgroundColor: 'red'}),
green: Style({backgroundColor: 'green'})
}
c.style = Style({
color: 'blue',
$state: function(state) {
if(state.success) {
if(state.late) {
return colorStyles.yellow
} else {
return colorStyles.green
}
} else {
return colorStyles.red
}
}
})
c.state.set("success", true) // container's background turns green
c.state.set("late", true) // container's background turns yellow
In the above example, the container goes through all 3 backgroundColor colors as its state changes. In all states, the text color will be blue tho, since the $state style mixes with the primary style properties.
<BlockName>
This sets a style for the Block
with the given name. Only blocks within the block who's style this is are affected, blocks that do not descend from the styled block, and even the styled block themselves are not affected. For example:
var stylish = Style({
Text: {
color: 'red'
}
})
var container = Container([Text('a')])
var text = Text("b")
container.style = stylish
text.style = stylish
In the above example, only "a" is styled red. The Text
"b" remains the default, black.
You can also give Blocks a Style
object, which is the same as the above form, except that the object-immediate is passed into the Style
constructor:
var textStyle = Style({
color: 'red'
})
var stylish = Style({
Text: textStyle
})
Keep in mind that Block
styles are inherited by their parent in-full (not line-by-line like in css). So any Block
that isn't given its own explicit style inherits from its ancestors (if its ancestors have a style for that Block
). For example,
var a,b,c,d,e, dContainer
var tree = Container([
a = Text('a'),
Container([
b = Text('b'),
c = Text('c'),
dContainer = Container([
d = Text('d'),
Container([
e = Text('e')
])
])
])
])
tree.style = Style({
Text: {color: 'green'}
})
c.style = Style({
fontWeight: 'bold'
})
dContainer.style = Style({
Text: {textDecoration: 'underline'}
})
I hope you don't mind I assigned variables inside the Block
structure - don't worry, the structure would be the same if the variables weren't assigned, but assigning the variables allows me to manipulate them after the structure is defined.
In any case, in the above example, the tree
object is given a style where Text
blocks are green. However, dContainer
is given an alternate Text
style.
How does that affect the resulting style? Well, "a" and "b" are colored green, but "d" and "e" are not green. Instead, "d" and "e" are the default color, black, and are underlined. This is because "d" and "e" inherit the Text
style from dContainer
which overrides the Text
style given to tree
.
And what about "c" you ask? Since "c" is given its own explicit style, that style also overrides any inheriting style. So "c" is bold and the default black.
$<label>
Block
objects can be given a label
property, which can be used to identify Block
objects of the same type that have different purposes within their parent.
This is essentially analogous to giving divs class names, and then styling using that class, except that it works in blocks.js's hierarchical way of course. Note, tho, that a Block
can have only one label.
For example:
var container = Container([
Text("header", "Your Receipt, Sir: "),
Text("receipt", "1 bagel - $5, 3 buffulo - $45, 3 sticks dynamite - $100, 45 tons of wheat - $200")
Text("Thank you for using butler-copter!")
])
container.style = Style({
Text: {
fontWeight: 'bold',
color: 'blue'
},
$header: {color: 'gray'},
$receipt: {color: 'green'}
})
In the above example, the text "Your Receipt, Sir: "
will be gray, the receipt text will be green, and the thank-you text
will be blue. Only the thank-you text will be bold.
Note that $label
styles override block styles, even if the block style is "closer" to the block. For example, in the following
example, the text "hi" will be gray, not blue.
var container = Container([
Container([
Text("hi")
])
])
container.style = Style({
$someLabel: {color: 'gray'},
Container: {
Text: {color: 'blue'}
}
})
$$<pseudoclass>
Pseudoclasses filter out which Block
styles are given to. Also, the styles mix with the styles defined in the style-definition containing it. For example:
var x = Text("hi")
x.style = Style({
fontWeight: 'bold',
$$hover: {color: 'red'}
})
The above code changes the text from bold-black to bold-red when you hover over it, and back to black again when you move your mouse off the text.
Pseudoclasses also mix with each other when applicable. For example:
var container = Container([Text("a"), Text("b")])
container.style = Style({
Text: {
$$lastChild: 'bold',
$$hover: {color: 'red'}
}
})
In the above code, "a" will start black and change to red when you hover over it. "b" will start black and bold, but will change to red and bold when you hover over it.
To set a style only when multiple pseudoclasses apply, simply nest them. For example:
var text = Text("a")
text.style = Style({
$$lastChild: {
$$hover: {color: 'red'}
}
})
In the above code, "a" will turn red if it is both the last child of its parent and is hovered over.
Also, pseudoclasses may take parameters, which are passed in with parens like a javascript function. For example:
var c = Container([Text("a"),Text("b"),Text("c"),Text("d"),Text("e")])
c.style = Style({
Text: {
'$$nthChild(1+2n)': {color: 'red'},
}
})
In the above code, "a", "c", and "e" are red, while "b" and "d" are black (the default).
$inherit
The $inherit
property, if set to true
, indicates that the style inherits properties from the style "above" it - the
style that would be used if the current style wasn't there. For example in the following, the text inside the container gets a green background,
but also a red text color:
Style({
Text: {color: 'red'},
Container: {
Text: {
$inherit: true,
backgroundColor: 'green'
}
}
})
In the following, a Text block with the label 'boom' would have both a green background and red text, whereas a Text block without that label, would not have the background color:
Style({
Text: {color: 'red'},
$boom: {
$inherit: true,
backgroundColor: 'green'
}
})
Note that $inherit
is ignored the top-level of psuedoclass styles, $state
styles, and defaultStyle
s since they always inherit.
Style
objects can be as simple as a few standard css properties, or can take the place of a whole css stylesheet and more. Here's an example of a more complex style:
var topBarHeight = 100
Style({
marginTop: topBarHeight,
Button: {
$setup: function(block) {
var handler;
block.on('moo', handler=function() {
console.log("He won't stop mooing!")
})
return {handler:handler}
},
$kill: function(block, setupState) {
block.off('moo',setupState.handler)
}
},
$closeButton: {
//future: $inherit: true, // inherits the Button style (if the block is a Button)
position: 'absolute',
right: 3, top: 3,
width: 'calc(50% - 2px)'
},
Table: {
TableHeader: {
TableCell: {
borderBottom:'1px solid #000'
}
},
TableRow: {
'$$nthChild(1)':{
TableCell: {
borderTop: '1px solid #000'
}
},
TableCell: {
'$$nthChild(1)': {
borderLeft: "1px solid #000"
},
$$lastChild: {
borderRight: "1px solid #000"
}
},
$$lastChild: {
TableCell: {
borderBottom: "1px solid #000",
'$$nthChild(1)': {
borderLeft: "1px solid #000",
},
$$lastChild:{
borderRight: "1px solid #000",
}
}
}
}
},
TopBar: {
marginTop: -topBarHeight+2,
position: 'absolute',
right: 0,
Search: {
position: 'relative',
top: -3,
$field:{
height: 23
}
},
DropTab: {
position: 'static',
$wrapper: {
position: 'static'
},
$menu: {
position: 'absolute',
border: border,
marginTop: 1,
backgroundColor: 'white',
cursor: 'pointer',
Text: {
color: 'bonkers'
}
},
$button: {
border: border,
fontSize: 24,
fontWeight: 'bold'
}
},
$userDropTab: {
//future: $inherit: true, inherits from DropTab above
cursor: 'pointer'
},
}
})
styleObject.mix
styleObject.mix(styleObject2)
styleObject.mix(styleDefinition)
Returns a new style that combines together calling style object and the passed style object or style definition. The properties from the passed style object override the ones from the calling object.
Examples:
var newStyle = oldStyle.mix({
color: 'red'
})
var newStyle2 = oldStyle.mix(anotherStyle)
styleObject.copy()
Returns a new style that is a copy of the calling style object but has a new className
. Written for internal use.
Style.addPseudoClass
Style.addPseudoClass(name, fns)
- Creates a new pseudoclass that can be used in Style
objects. This can be used to create all-new psuedoclasses no one's ever thought of before!
name
- The name of the new pseudoclassfns
- An object with the members:
check(block, processedParameter)
- A function that returns true if the pseudoclass applies to passed block
setup(block, startCallback, endCallback, processedParameter)
- A function that should call startCallback()
when the pseudoclass starts applying, and endCallback()
when it stops applying. Can return a state
object that will be passed to the kill
function.
processedParameter
- The parameter passed to the pseudoclass (e.g. in ":not(:first-child)"
, ":first-child" is the parameter). If a processParameter
function is given, this will be the return value of that function.kill(block, state)
- A function that cleans up any event listeners or anything else set up in the setup
function.emulated
- (Optional - default false) Set to true if this implements a native pseudoclass. If true
, Blocks will attempt optimize the pseudoclass using native css if possible.processParameter(parameter)
- (Optional) Takes the pseudoclass parameter and returns some object representing it that will be used by the setup
and check
functions.parameterTransform(parameter)
- (Optional) Returns a modified version of the passed parameter. This is useful in cases where native pseudoclass parameter parsing is unnecessarily strict (eg. nth-child parameters)Any pseudoclass that exists in standard css can be used by blocks.js, even if it isn't build-in with a js-rendered emulation. The catch is that their use is limited. The following things aren't supported for these:
$setup
, $kill
, or $state
functions within the pseudoclass style definitionhover
- The usual :hover pseudoclasschecked
- The usual :checked pseudoclassrequired
- The usual :required pseudoclasslastChild
- The usual :last-child pseudoclassnthChild(a+bn)
- The usual :nth-child pseudoclass (with more tolerant parameter parsing)Note that, while the list of built-in pseudoclasses is currently short, all standard pseudoclasses can be defined except the ":visited" pseudoclass, because the necessary information is not available via javascript (a browser "security" policy).
Blocks.js unifies the default styles of dom nodes - all objects that inherit directly from Block
have the same default styling unless they define their defaultStyle
property.
The base default is mostly the same as css's base default. The two defaults that are different for Block
objects:
display
- "inline-block"
position
- "relative"
box-sizing
- "border-box"
(excepting <img>
nodes, which are still defaulted to content-box
because pixel perfect image sizing is often important)Also, while most css styles are not inherited from a Block
's parent, the following are inherited:
color
cursor
fontFamily
fontSize
fontStyle
fontVariant
fontWeight
visibility
And while blocks.js generally rejects css's use of cascading, there is some similar cascading going on, but much more simplified and localized. Defining this behavior in terms of "cascading order" (where later additions override earlier), the order is:
defaultStyle
property of the block instance's furthest ancestor classdefaultStyle
s in the Block's ancestry)defaultStyle
property of the Block's parent classdefaultStyle
property of the Block itselfstyle
property)Often in traditional web development, all the HTML will be rendered and any javascript for them initialized on page load, and the elements that shouldn't be shown to the user are simply hidden, and then shown when needed. Using blocks.js, its recommended that you create and remove nodes as needed, rather than showing and hiding (using visible
). The only reason to use the show/hide technique is if the element in question is particularly expensive to generate.
Block.label
is not dynamic (can't be changed) because it is intended to be used to identify a particular Block when multiple Blocks of the same type are used alongside eachother. If you're looking for a way to change styles dynamically, use Block.state
.blocks.js
is notBlocks.js is not:
have an event a block will emit when it or one of its ancestors becomes detached from the dom
consider adding vertical-align:top to the default css, since it solves weird issues with inline-blocks causing extra bottom-margin: http://stackoverflow.com/questions/20310690/overflowhidden-on-inline-block-adds-height-to-parent
Implement an $inherit option on Styles, so that they can implicitly inherit from styles above them without specifying which style to combine into it
Emulate the :not psuedoclass
Figure out how to support animations, @keyframes and that kind of thing
support css animations
var animation = Style.Animation({
name: 'slidein' // produces a css style like __defaultName__2_slidein to prevent name collisions
from: {
margin-left: 100%,
width: 300%
},
'75%': {
width: '200%'
},
to: someStyleObject
})
Style({
anim: animation, // anim cause its short and animation is already taken by plain css
animationDuration: 300 // milliseconds
})
* Make sure its easy to dynamically create many-stepped animations, eg: http://www.joelambert.co.uk/morf/
* http://stackoverflow.com/questions/18481550/how-to-dynamically-create-keyframe-css-animations
Maybe if a block has an explicit style set, it ignore's any styling from its parent (ie the componentStyleMap)
user-defined style properties
Finish MultiSelect (currently may not fire certain events with certain ways of selecting things with the mouse)
Make all controls usable via the keybaord
Consider making Style objects dynamically changable, and also inheritable/extendable so that you can extend the style object of a Block instead of having to extend the object passed to a Style prototype
in separate module (a Blocks utility kit or something):
Optimization ideas:
addAt
method and .style
setter by between 10 and 30 times by
block.attach
method and Blocks.attach
function to take an optional first parameter - a domNode to append to in place of document.body
Blocks.attach
function can no longer take varargs of blocks (eg Blocks.attach(block1, block2, block2)
- instead do Blocks.attach([block1, block2, block2])
)attach
function or method. Without this, styles won't be rendered.processParameter
in addPseudoClass
optional like the docs sayStyle
objects (that use any Style feature)
* Optimizing pseudoclass styles when their style branch can be rendered in pure-css
* defaultStyle
styles can be arbitrary Style objects now
* $state styles can be arbitrary Style objects now
* $label changed from being a modifier on a Block style to indicating a whole new labeled block style (see section on $label for details)
* augmenting nth-child to be able to be more sane in how it processes its input (you can reverse the order of the terms and whitespace is tolerated)
* changing the default of box-sizing to 'border-box' except for images, which retain the 'content-box' defaultundefined
is passed as a style, it is now ignored
* fixing bug: an array of blocks couldn't be passed to table.cell
ifon
and ifoff
for proxying browser events through Blocks
* Override the on
method so that standard browser events are automatically attached to domNodes
* provide a way to exclude certain events, so they can be set up in an alternate wayifon
and ifoff
methodsWant to contribute? Start with the Contributing Guide!
Anything helps:
Released under the MIT license: http://opensource.org/licenses/MIT
FAQs
A library for building and styling web components in pure-javascript.
We found that blocks.js demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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