JavaScript object query engine
STATUS: Jora is still very much work in progress. Syntax may change in next releases.
Features:
Related projects:
TODO:
More ideas and thoughts: Jora todo gist, Jora ToDo on Discovery.js projects state overview
Table of content:
npm install jora
In node.js
const jora = require('jora');
For a browser unminified (dist/jora.js) and minified (dist/jora.min.js) builds are available:
<script src="node_modules/jora/dist/jora.js"></script>
<script src="node_modules/jora/dist/jora.min.js"></script>
<!-- or use one of CDN -->
<script src="https://unpkg.com/jora/dist/jora.js"></script>
<script src="https://cdn.jsdelivr.net/npm/jora/dist/jora.js"></script>
const jora = require('jora');
// create a query
const query = jora('foo.bar');
// or with custom methods
const queryWithCustomMethods = jora('foo.myMethod()', {
methods: {
myMethod(current) { /* do something and return a new value */ }
}
});
// perform a query
const result = query(data, context);
Options:
methods
Type: Object
Default: undefined
Additional methods for using in query passed as an object, where a key is a method name and a value is a function to perform an action. It can override build-in methods.
debug
Type: Boolean or function(name, value)
Default: false
Enables debug output. When set a function, this function will recieve a section name and its value.
tolerant
Type: Boolean
Default: false
Enables tolerant parsing mode. This mode supresses parsing errors when possible.
stat
Type: Boolean
Default: false
Enables stat mode. When mode is enabled a query stat interface is returning instead of resulting data.
Get npm dependency paths (as a tree) that have packages with more than one version:
const jora = require('jora');
function printTree() {
// see implementation in examples/npm-ls.js
}
require('child_process').exec('npm ls --json', (error, stdout) => {
if (error) {
return;
}
const npmTree = JSON.parse(stdout);
const tree = JSON.parse(stdout);
const depsPathsToMultipleVersionPackages = jora(`
$normalizedDeps: => dependencies.entries().({ name: key, ...value });
$multiVersionPackages:
..$normalizedDeps()
.group(=>name, =>version)
.({ name: key, versions: value.sort() })
.[versions.size() > 1];
$pathToMultiVersionPackages: => .($name; {
name,
version,
otherVersions: $multiVersionPackages[=>name=$name].versions - version,
dependencies: $normalizedDeps()
.$pathToMultiVersionPackages()
.[name in $multiVersionPackages.name or dependencies]
});
$pathToMultiVersionPackages()
`)(tree);
printTree(depsPathsToMultipleVersionPackages);
});
Example of output:
jora@1.0.0
├─ browserify@16.2.2
│ ├─ assert@1.4.1
│ │ └─ util@0.10.3 [other versions: 0.10.4]
│ │ └─ inherits@2.0.1 [other versions: 2.0.3]
│ ├─ browser-pack@6.1.0
│ │ └─ combine-source-map@0.8.0
│ │ ├─ source-map@0.5.7 [other versions: 0.6.1, 0.4.4, 0.2.0, 0.1.43]
│ │ └─ inline-source-map@0.6.2
│ │ └─ source-map@0.5.7 [other versions: 0.6.1, 0.4.4, 0.2.0, 0.1.43]
│ ├─ browser-resolve@1.11.3
│ │ └─ resolve@1.1.7 [other versions: 1.8.1]
│ ├─ concat-stream@1.6.2
│ │ └─ inherits@2.0.3 [other versions: 2.0.1]
...
| Jora | Description |
|---|---|
| 42 -123 4.22 1e3 1e-2 | Numbers |
| "string" 'string' | Strings |
| /regexp/ /regexp/i | A JavaScript regexp, only i flag supported |
| { } | Object initializer/literal syntax. Spread operator (...) can be used, e.g. { a: 1, ..., ...foo } (... with no expression on right side the same as ...$) |
| [ ] | Array initializer/literal syntax. Spread operator (...) can be used, e.g. [1, ..., ...foo] (... with no expression on right side the same as ...$). Unlike JavaScript, spread operator in jora inlines arrays only and left as is any other values, i.e. [...[1, 2], ...3, ..."45", { "6": 7 }] -> [1, 2, 3, "45", { "6": 7 }] |
| => e < block > (deprecated) | A function NOTE: Syntax < block > is deprecated, avoid to use it |
| query asc query desc query asc, query desc, ... | A sorting function that takes two arguments and compare query result for each in specified order (asc – ascending, desc – descending) |
Following keywords can be used with the same meaning as in JavaScript:
truefalsenullundefined| Jora | Description |
|---|---|
| x + y | Add In case one of the operands is an array it produces new array with elements from `x` and `y` excluding duplicates |
| x - y | Subtract In case one of the operands is an array with elements from `x` excluding elements from `y` |
| x * y | Multiply |
| x / y | Divide |
| x % y | Modulo |
| Jora | Description |
|---|---|
| x = y | Equals (as === in JS) |
| x != y | Not equals (as !== in JS) |
| x < y | Less than |
| x <= y | Less than or equal to |
| x > y | Greater than |
| x >= y | Greater than or equal to |
| x ~= y | Match operator, behaviour depends on y type:RegExp – test against regexp function – test like filter()null or undefined – always truthyanything else – always falsy |
| Jora | Description |
|---|---|
| ( x ) | Explicity operator precedence. Definitions are allowed (i.e. ($a: 1; $a + $a) see bellow) |
| x or y | Boolean or.Equivalent to || in JS, but x tests with bool() method |
| x and y | Boolean and.Equivalent to && in JS, but x tests with bool() method |
| not x no x | Boolean not.Equivalent to && in JS, but x tests with bool() method |
| x ? y : z | If x is truthy than return y else return z. x tests with bool() method |
| x in [a, b, c] [a, b, c] has x | Equivalent to x = a or x = b or x = c |
| x not in [a, b, c] [a, b, c] has no x | Equivalent to x != a and x != b and x != c |
Some constructions suppose to use a block, which may consists of a variable definition list (should comes first) and an expression. Both are optional. When an expression is empty, a current value (i.e. $) returns.
The syntax of definition (white spaces between any part are optional):
$ident ;
$ident : expression ;
For example:
$foo:123; // Define `$foo` variable
$bar; // The same as `$bar:$.bar;` or `$a: bar;`
$baz: $foo + $bar; // Definitions may be used in following expressions
In terms of JavaScript, a block creates a new scope. Once a variable is defined, its value never change. Variables can be redefined in nested scopes, but can't be duplicated in the same scope - it causes to error.
| Jora | Description |
|---|---|
| $ | A scope input data (current value). On top level scope it's the same as @. In most cases it may be omitted. Used implicitly an input for subquery when no other subjects is defined (e.g. foo() and .foo() are equivalent for $.foo()). |
| $$ | A reference to the second parameter of closest function or undefined when no such |
| @ | A query input data |
| # | A query context |
Since Jora's query performs as query(data, context), in terms of Jora it looks like query(@, #).
| jora | Description |
|---|---|
| ident | The same as $.ident |
| .ident | Child member operator (example: foo.bar.baz, #.foo['use any symbols for name']) |
| ..ident ..( block ) | Recursive descendant operator (example: ..deps, ..(deps + dependants)) |
| .[ block ] | Filter a current data. Equivalent to a .filter(<block>) |
| .( block ) | Map a current data. Equivalent to a .map(<block>) |
| method() .method() ..$method() | Invoke a method to current value, where $method is a reference to definition value (i.e. $example: => $ * 10; 2.$plural(["example", "examples"])). Can take arguments (i.e. $method(one, 2)). |
| $method() .$method() ..method() | Invoke a method to current value. See build-in methods below |
| path[expr] | Array-like notation to access properties. Behaves like pick() method. In case you need to fetch a value to each element of array use .($[expr]) or map(=>$[expr]) |
| [from:to] [from:to:step] | Slice notation. Examples: $str: '<foo>'; str[1:-1] (result is 'foo') or $ar:[1,2,3,4,5,6]; $ar[-3::-1] (result is [6,5,4]) |
| expr | [definitions] expr | ... | Pipeline operator. It's useful to make a query value as current value. Approximately this effect can be obtained using variables: $ar: [1,2,3]; { size: $ar.size(), top2: $ar[0:2] }. However, with pipeline operator it's a bit simplier and clear: `[1,2,3] |
| jora | Description |
|---|---|
| bool() | The same as Boolean() in JS, with exception that empty arrays and objects with no keys treats as falsy |
| keys() | The same as Object.keys() in JS |
| values() | The same as Object.values() in JS |
| entries() | Similar to Object.entries() in JS with a difference: { key, value } objects is using for entries instead of array tuples |
| fromEntries() | Similar to Object.fromEntries() in JS with difference: { key, value } objects are expecting as entries instead of array tuples |
| pick("key") pick(index) pick(fn) | Get a value by a key, an index or a function. It returns an element with e index for arrays, a char with e index for strings, and a value with e key (must be own key) for enything else. Negative indecies are supported for arrays and strings. Current value is element for an array, a char for a string or an entry value for object. Arg1 (i.e. $$) is an index for arrays and strings, and a key for objects. |
| size() | Returns count of keys if current data is object, otherwise returns length value or 0 when field is absent |
| sort(<fn>) | Sort an array by a value fetched with getter (<fn>). Keep in mind, you can use sorting function definition syntax using asc and desc keywords, qhich is more effective in many ways. In case of sorting function definition usage, < and > are not needed and you can specify sorting order for each component. Following queries are equivalents:sort(<foo.bar>) and sort(foo.bar asc)sort(<foo>).reverse() and sort(foo desc)sort(<[a, b]>) and sort(a asc, b asc) |
| reverse() | Reverse order of items |
| group(<fn>[, <fn>]) | Group an array items by a value fetched with first getter. |
| filter(<fn>) | The same as Array#filter() in JS |
| map(<fn>) | The same as Array#map() in JS |
| split(pattern) | The same as String#split() in JS. pattern may be a string or regexp |
| join(separator) | The same as Array#join() in JS. When separator is undefined then "," is using |
| slice(from, to) | The same as Array#slice() or String#slice() in JS |
| match(pattern, matchAll) | Similar to String#match(). Since regexp'es in jora doesn't support for g flag, use matchAll argument to get all matches, i.e. 'abcabc'.match(/ab/, true) (jora) instead of 'abcabc'.match(/ab/g) (JS) |
| reduce(fn[, initValue]) | The same as Array#reduce() in JS. Use $$ to access to accumulator and $ to current value, e.g. find the max value reduce(=>$ > $$ ? $ : $$) |
MIT
1.0.0-beta.2 (May 17, 2020)
FAQs
JavaScript object query engine
The npm package jora receives a total of 29,780 weekly downloads. As such, jora popularity was classified as popular.
We found that jora demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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