deleight

Deleight

Deleight is a library now comprising 9 modules designed to improve expressiveness without compromising simplicity, performance, flexibility and sheer elegance of pure JavaScript. We achieve this by creating higher level functions, classes and objects which can get more done with less code than standard JavaScript primitives. These new primitives have been assembled into multiple submodules based on functionality and dependency so that you can include only the parts you need in your projects. The whole architecture means you can benefit from more expressiveness without compromising the sheer power and freedom of vanilla JavaScript.

Usage

import { apply } from 'deleight/dom/apply';
import { map, range, forEach, zip } from 'deleight/generators';
apply({
    main: ([main]) => {
        const newContent = map(range(101, 120), i => `My index is  now ${i}`);
        const lastChildren = map(main.children, c => c.lastElementChild);
        forEach(zip(lastChildren, newContent), ([el, c]) => el.textContent = c);
    }
});

Deleight has been written in TypeScript. Using TypeScript helps to provide more guarantees about runtime perfornce because of the type enforcements and other helpful things at compile time. Also most of the primitives are well tested and have been further enhanced from earlier versions of Deleight. Deleight was already among the best performing frameworks in the Krausest frameworks benchmark before major work to restructure and improve the whole ibrary for Deleight 5.

Installation

Deleight has been compiled into ES modules anc CommonJS so that many project structures can benefit from it. You can simply throw any deleight modules into your web page and they will load fast and work well. All the modules are focused on particular tasks and have small file sizes, even unminified.

npm install deleight

or

import { object } from "https://cdn.jsdelivr.net/npm/deleight/dist/esm/deleight.min.js"

import { apply } from 'deleight/dom/apply';
import { range, map, chain } from 'deleight/generators';

If you use NPM to build your frontend, you can bring anything from the whole Deleight package into your files to access the full power of the library.

import { dom, Generator } from 'deleight';
const apply = dom.apply;
const { range, map, chain } = Generator;

Documentation

Deleight is easy to learn. Both the modules and the primitives in them are self-containing. In editors like VS Code, simply importing a function or a class will be all you need to learn what it does and how to use it. You will also find many examples (still adding more examples) that show them in action. Beyond this, you only need a bit of context about what a particular module is about so that you know when you need it and what to expect when you reach for it. You can learn a single function or class and benefit from it. There is no need to learn Deleight from the top down. Still an API documentation is available if you prefer this.

Modules

css

Primitives to help with loading and using stylesheets. Using css, we can

• create CSS stylesheets from CSS files or text
• extract CSS stylesheets from a document tree from style and link elements, optionally removing them from the tree
• add or remove a CSS stylesheet to/from multiple documents, fragments or elements (using shadow roots) at the same time.
• locate and manipulate rules within a stylesheet with string (selector) keys.

dom

Primitives for working with the DOM. Using dom, we can apply components to elements either by matching with selectors or by specifying the components with attributes. Many standard components have been included for creating event handlers, setting attributes and setting and assigning properties.

function

Currently exports 2 primitives:

• A Return function that creates an object that represents the return value of calling a function. Accessing members of the object will first call the function to get the object before accessing properties in it.

• A setContext function which wraps a given function with another function that includes the context object in its scope. setContext can be called on multiple functions to return functions which run mutually exclusively. These can be useful, for example, event handlers that create network requests so they do not repeat the request before an earlier request has recieved and processed a result.

generators

Many powerful generators to minimize computations and memory use. Some are seen in the usage example.

lists

Objects implementing an array-like mutation interface so they can be used together or, in the case of ElementList, provide a more 'array-like' usage pattern.

object

Many important primitives for manipulating objects or getting stuff done with them. The apply and process functions of the dom module use the object versions under the hood. There are also shared and deep member sub-modules for respectively accessing members in multiple objects or members deep within an object.

We have seen the benefits of using shared members in the JS Frameworks Benchmarks and deep member access can be used to trivially implement routing.

import { call } from 'deleight/object/deepmember'

const routes = {
    blog: {
        post(title) { 
            return () => {

            }
        },
        posts(page) {

        }
    },
    news(article) {

    }
}

function router(newHash) {
    const path = newHash.split('/');
    call(routes, path);
}

// Hey this router could be slow if poorly implemented. But you get the idea...

process

Exports the Process primitive which converts every iterable into a callable, providing they contain one or more Step objects. Steps provide the interpretations for the values is the iterable after it, up to the next step with equal or lower priority.

Many simple steps have been implemented to do things like call functions with the same scope and arguments, pipe functions, access properties on multiple objects, spread and compact values, etc.

Think of processes as functions where we can treat all the lines as items in an array and so manipulate them however we want. We can also define the meaning of all the keywords. It is helpful for creating DSLs or generating code on the fly, such as from markup.

proxy

Many useful proxies including Alias and Scope for creating virtual objects, Selector for treating descendant elements as simple properties and Wrapper to wrap any objects and perform pre or post processing on member access.

template

Functions for creating template functions from pre-existing text, such as those loaded from a file. This is important because JS template literals must be created 'immediately'. Created templates can be either syn and async, return a single rendered text or an iterable of rendered text or promises that resolve to rendered text.

Deleight has matured a lot in a short time. This has meant there has been many large-scale changes over the last couple of months. For some, this may raise questions about the stability of the project. However, Deleight of today is already so powerful and minimal that you rarely need to worry about ongoing support. Also the current structure could be stable for a vary long time, because we have done a lot of work to find the best primitives we know for the different tasks.