Roll your own framework experiment

client-side-framework.ts

import { isFunction } from 'util';

abstract class Listener {
    
    protected listeners: { [eventName: string]: [Function] } = {};

    public on(eventName: string, callback: Function) {
        this.listeners[eventName] = this.listeners[eventName] || [];
        this.listeners[eventName].push(callback);
    }

    protected raise(eventName: string, payloadArgs: any[]) {
        this.listeners[eventName] = this.listeners[eventName] || [];
        this.listeners[eventName].forEach((callback: Function) => {
            callback.apply(this, payloadArgs);
        });
    }

}

class Data extends Listener {

    protected data: { [key: string]: any } = {};

    constructor(data?: any, prefix: string = '') {
        super();
        if (data) {
            this.apply(data, prefix);
        }
    }

    protected _set(key: string, value: any) {
        const oldValue: any = this.data[key];
        this.data[key] = value;
        this.raise.call(this, 'set', [key, value, oldValue]);
    }

    public set(key: string, value: any) {
        if (!/^[a-z0-9]/.test(key)) {
            throw new Error('Data key must start with a letter or number');
        }
        this._set(key, value);
    }

    public get(key: string): any {
        return this.data[key];
    }

    public apply(data: any, prefix: string = '') {
        if (typeof data == 'object' || Array.isArray(data)) {
            for (let key in data) {
                this._set(prefix + key, data[key]);
            }
        }
        else {
            this._set('.', data);
        }
    }

}


class Component extends Listener {

    protected directive: ComponentDirective;
    protected $element: JQuery;
    protected dataBindings: string[] = [];

    constructor(directive: ComponentDirective, $element: JQuery) {
        super();
        this.directive = directive;
        this.$element = $element;
    }

    public element(): JQuery {
        return this.$element;
    }

    public find(selector: string): JQuery {
        return this.$element.find(selector);
    }

    protected addBinding(key: string) {
        this.dataBindings.push(key);
    }

    protected getReplacedHtml(html: string, data: Data, bind: boolean = true) {
        const compontent: Component = this;
        html = html.replace(/{{([^}]+)}}/g, function (wholeMatch, key) {
            key = $.trim(key);
            var substitution = (function () {
                return data.get(key);
            })();
            if (bind) {
                compontent.addBinding(key);
            }
            return (substitution === undefined ? wholeMatch : substitution);
        });
        return html;
    }

    protected parseTemplate(data: Data): string {
        const compontent: Component = this;
        let html: string = this.directive.template().html();
        this.dataBindings = [];
        html = this.getReplacedHtml(html, data);
        return html;
    }

    public render(data: Data) {
        const compontent: Component = this;
        this.$element.html(this.parseTemplate(data));
        this.$element.find('[each]').each((index: number, element: HTMLElement) => {
            const $loop: JQuery = $(element);
            const dataKey: string = $loop.attr('each') || '';
            const array: any = data.get(dataKey);
            if (Array.isArray(array)) {
                this.addBinding(dataKey)
                array.forEach((value: any) => {
                    let $item = $loop.clone();
                    let data: Data = new Data(value, '.');
                    $item.html(
                        compontent.getReplacedHtml($item.html(), data, false)
                    )
                    $loop.before($item);
                });
            }
            $loop.remove();
        });
        this.$element.find('[if]').each((index: number, element: HTMLElement) => {
            const $if: JQuery = $(element);
            const statement: string = $if.attr('if') || '';
            let isTrue: boolean = false;
            if (/^[a-z0-9][a-z0-9_]+$/i.test(statement)) {
                this.addBinding(statement);
                isTrue = !!data.get(statement);
            }
            if (!isTrue) {
                $if.remove();
            }
        });
        this.$element.find('[not]').each((index: number, element: HTMLElement) => {
            const $not: JQuery = $(element);
            const statement: string = $not.attr('not') || '';
            let isFalse: boolean = true;
            if (/^[a-z0-9][a-z0-9_]+$/i.test(statement)) {
                this.addBinding(statement);
                isFalse = !data.get(statement);
            }
            if (!isFalse) {
                $not.remove();
            }
        });
        this.$element.attr('data-bindings', this.dataBindings.join(' '))
            .data('component', this);
    }

}


class ComponentDirective extends Listener {

    protected $directive: JQuery;
    protected name: string;
    protected href: string;
    protected $content: JQuery | null = null;
    protected listeners: { [eventName: string]: [Function] } = {};

    constructor(app: App, $directive: JQuery) {
        super();
        this.$directive = $directive;
        this.name = $directive.attr('name') || '';
        this.href = $directive.attr('href') || '';
        if (this.name.length == 0) {
            throw new Error('Must have a name attribute.')
        }
        if (this.href.length == 0) {
            throw new Error('Must have a href attribute.')
        }
    }

    protected find(selector: string): JQuery {
        if (this.$content === null) {
            throw new Error('Must load the component first.');
        }
        return this.$content.find(selector);
    }

    public root(): JQuery {
        if (this.$content === null) {
            throw new Error('Must load the component first.');
        }
        return this.$content;
    }

    public template(): JQuery {
        return this.find('template');
    }

    public load(): Promise<ComponentDirective> {
        const component: ComponentDirective = this;
        return new Promise((resolve, reject) => {
            if (component.$content !== null) {
                return resolve(component);
            }
            $.get(component.href).then(function (response) {
                component.$content = $('<component>' + response + '</component>');
                component.raise('loaded', [component]);
                resolve(component);
            }).catch((err) => {
                reject(err);
            });
        });
    }

}


class App {

    protected $root: JQuery;

    public routerView: null | JQuery = null;
    public components: { [name: string]: ComponentDirective } = {};
    public data: Data = new Data();

    constructor(rootSelector?: string) {
        this.$root = $(rootSelector || 'html');
        const app = this;
        this.findComponentDirectives(this.$root);
        this.$root.bind('DOMNodeInserted', function (e) {
            let $el = $(e.target);
            let tagName: string = e.target.tagName.toLocaleLowerCase();
            
        });
        this.$root.on('click', 'a[href^="@"]', function (e) {
            e.preventDefault();
            const $el: JQuery = $(this);
            if (typeof $el != 'undefined') {
                const link: string | undefined = $el.attr('href');
                const target: string = $el.attr('target') || '';
                if (typeof link != 'undefined' && link.length > 0) {
                    const directive: ComponentDirective = app.components[link.substr(1)];
                    if (typeof directive != 'undefined') {
                        const $target = target.length ? $(target) : $('[router-output]');
                        directive.load().then(() => {
                            app.replaceElement($target, directive);
                        });
                    }
                }
            }
        });
        this.data.on('set', function (key: string) {
            const elements: JQuery = $('[data-bindings~="' + key + '"]');
            elements.each((index: number, element: HTMLElement) => {
                const component: Component = $(element).data('component');
                if (typeof component != 'undefined') {
                    component.render(app.data);
                }
            });
        });
    }

    public replaceElement($el: JQuery, directive: ComponentDirective) {
        const app: App = this;
        const component: Component = new Component(directive, $el.clone());
        component.render(app.data);
        component.find(Object.keys(this.components).join(',')).each(function () {
            const $replace: JQuery = $(this);
            const directive: ComponentDirective = app.components[this.tagName.toLocaleLowerCase()];
            directive.load().then(() => {
                const component: Component = new Component(directive, $replace);
                component.render(app.data);
            });
        });
        $el.after(component.element()).remove();
    }

    protected parseTemplate(html: string): string {
        const app: App = this;
        html = html.replace(/{{([^}]+)}}/g, function (wholeMatch, key) {
            var substitution = app.data[$.trim(key)];
            return (substitution === undefined ? wholeMatch : substitution);
        });
        return html;
    }

    protected findComponents($element) {
        $element.find(Object.keys(this.components).join(','))
            .each((index: number, htmlElement: HTMLElement) => {
                let componentName: string = htmlElement.tagName.toLocaleLowerCase();
                
            });
    }

    protected findComponentDirectives($container: JQuery) {
        const app: App = this;
        $container.find('link[rel~="component"][name][href]')
            .each((index: number, htmlElement: HTMLElement) => {
                const $el: JQuery = $(htmlElement);
                let name: string = $el.attr('name') || '';
                let href: string = $el.attr('href') || '';
                if (typeof name != 'undefined' && typeof href != 'undefined') {
                    app.foundComponentDirective(name, $el);
                }
            });
    }

    protected foundComponentDirective(name: string, $el: JQuery): ComponentDirective {
        let directive: ComponentDirective = this.components[name];
        const app: App = this;
        if (typeof directive == 'undefined') {
            directive = new ComponentDirective(app, $el);
            this.components[name] = directive;
            // Listen for it to load
            directive.on('loaded', function () {
                app.findComponentDirectives(directive.root());
            });
            // If this component is already in the DOM, replace it right away
            this.$root.find(name).each(function () {
                directive.load().then(() => {
                    app.replaceElement($(this), directive);
                });
            });
        }
        return directive;
    }

}

contact.html

<link rel="component" name="dynamic" href="html/dynamic.html" />

<template>
    <strong>
        Contact Us
    </strong>
    
    <matt />

    <p>
        Hi, friends. This is my sample.
    </p>
    
    <a href="@dynamic">Lazy</a>

</template>

dynamic.html

<template>
    
    <p>
        This page is a component that was not referenced on the original page.
    </p>
    
    <a href="@contact">back</a>

</template>

home.html

<template>
    <p>
        Hello there, <strong>{{ name }}</strong>!
    </p>

    <p if="enabled">
        I am enabled
    </p>

    <ul if="list">
        <li each="list">{{ .id }}) {{ .name }}</li>
    </ul>
    <div not="list">
        Nothing to list.
    </div>

</template>

index.html

<!doctype html>
<html lang="en">

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <title>JS Framework Example</title>
    
    <link rel="stylesheet" href="https://unpkg.com/purecss@1.0.0/build/base-min.css">

    <link rel="component" name="home" href="html/home.html" path="/" />
    <link rel="component" name="contact" href="html/contact.html" path="/contact" />
    <link rel="component" name="matt" href="html/matt.html" />
</head>

<body>
    <div id="app">
        <header>
            <h1>JS Framework Example</h1>
            <nav>
                <a href="@home">Home</a>
                <a href="@contact">Contact Us</a>
            </nav>
        </header>
        <main router-output>
            <home>Loading...</home>
        </main>
    </div>
    
    <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
    <script src="app/main.js"></script>
    <script>
        let MyApp = new App();
        MyApp.data.apply({
            'name': 'Jason Byrne',
            'enabled': false,
            'list': [ 
                { id: 1, name: 'Florida' }, 
                { id: 2, name: 'Georgia' }, 
                { id: 3, name: 'Alabama' } 
            ]
        });
    </script>
</body>

</html>

matt.html

<template>

    <b>{{ name }} is awesome!!</b>

</template>