3
Dcfd680473
其他matti • 于 2018-04-04发布 • 50次阅读 • (原文: gitissue.com)
// /roki/index.js
const roki = function () {

    let oldvnode

    return {
        h,
        render
    }

    function isString(s) {
        return typeof s === 'string'
    }

    function h(type, props = {}, children = []) {
        children = children.map((child) => {
            if (isString(child)) return createTextVNode(child, void 0)
            return child
        })
        return createVNode(type, props, props.key, children, void 0)
    }

    function patch(oldvnode = {}, vnode) {
        let element
        if (vnode.type) {
            if (oldvnode && oldvnode.type === vnode.type) {
                element = oldvnode.dom
                updateProps(element, vnode.props, oldvnode.props)
            } else {
                element = createElement(vnode.type, vnode.props)
            }
            vnode.children && patchChildren(oldvnode.children, vnode.children, element)
        } else if (vnode.text) {
            if (oldvnode.text) {
                element = oldvnode.dom
                if (vnode.text !== oldvnode.text) element.nodeValue = vnode.text
            } else {
                element = createTextNode(vnode.text)
            }
        }
        vnode.dom = element
        return vnode
    }

    function patchChildren(oldChildren = [], children = [], parentElement) {
        children.forEach((child, index) => {
            let oldChild = null
            if (oldChildren) oldChild = oldChildren[index]
            if (oldChild) {
                let newNode = patch(oldChild, child)
                if (oldChild.type !== child.type) {
                    replaceChild(parentElement, oldChild.dom, newNode.dom)
                }
            } else {
                let newNode = patch(undefined, child)
                appendChild(parentElement, newNode.dom)
            }
        })

        oldChildren.slice(children.length).forEach((child) => removeChild(parentElement, child.dom))
    }

    function render(vnode, container) {
        vnode = patch(oldvnode, vnode)
        if (!oldvnode) appendChild(container, vnode.dom)
        oldvnode = vnode
    }

    function createVNode(type, props, key, children, dom) {
        return {
            type,
            children,
            props,
            dom,
            key
        }
    }

    function createTextVNode(text, dom) {
        return {
            text,
            dom
        }
    }

    function removeChild(element, child) {
        element.removeChild(child)
    }

    function appendChild(element, child) {
        element.appendChild(child)
    }

    function replaceChild(element, oldChild, newChild) {
        element.replaceChild(newChild, oldChild)
    }

    function createElement(tag, props = {}) {
        const element = document.createElement(tag)
        updateProps(element, props)
        return element
    }

    function updateProps(element, props = {}, oldProps = {}) {
        Object.keys(oldProps)
            .filter((key) => !key.startsWith('on'))
            .forEach((key) => { element.removeAttribute(key) })

        Object.keys(oldProps)
            .filter((key) => key.startsWith('on'))
            .forEach((key) => {
                const eventType = key.toLowerCase().substring(2);
                element.removeEventListener(eventType, oldProps[key]);
            })

        Object.keys(props)
            .filter((key) => !key.startsWith('on'))
            .forEach((key) => { element.setAttribute(key, props[key]) })

        Object.keys(props)
            .filter((key) => key.startsWith('on'))
            .forEach((key) => {
                const eventType = key.toLowerCase().substring(2);
                element.addEventListener(eventType, props[key]);
            })
    }

    function createTextNode(text) {
        return document.createTextNode(text)
    }

}

window.Roki = roki()
html lang="en">

head>
    meta charset="UTF-8">
    meta name="viewport" content="width=device-width, initial-scale=1.0">
    meta http-equiv="X-UA-Compatible" content="ie=edge">
    title>Documenttitle>
head>

body>
    button id="update">updatebutton>
    div id="root">div>
    script src="./roki/index.js">script>
    script>
        const {
            render,
            h
        } = Roki

        let vnode = h('div', {}, [
            h('span', {
                style: 'font-weight:bold;',
                onclick: function () {
                    console.log('old span')
                }
            }, ['This is bold']),
            ' and this is just normal text',
            h('a', { href: '/foo' }, ['I\'ll take you places!']),
            h('br'),
            'this will delete'
        ])

        let newVnode = h('div', { onclick: function () { console.log('new div') } }, [
            h('span', { style: 'font-weight: normal; font-style: italic;' }, ['This is now italic type']),
            ' and this is still just normal text',
            h('a', { href: '/bar' }, ['I\'ll take you places!!!']),
            h('br'),
        ]);

        render(vnode, root)

        update.addEventListener('click', () => {
            console.log(222)
            render(newVnode, root)
        })

    script>
body>

html>
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