hg-sid/src/virtual-dom/h.js

a front-end simple framework with mvc

import { isArray, isPrimitive } from './util'
import VNode from './vnode'

function h (tagName, properties, children) {
  let childNodes = [] // 用于存放所有的子节点
  let tag = tagName
  let props, childs

  // 如果 properties 是数组，则默认是 children
  if (isArray(properties)) {
    props = {}
    childs = properties
  } else {
    props = properties || {}
    childs = children || []
  }

  if (tag) tag = normalizeTag(tag)
  props = normalizeProps(props)

  if (childs.length > 0) {
    addChild(childs, childNodes, tag, props)
  }

  return new VNode(tag, props, childNodes)
}

function addChild (c, childNodes, tag, props) {
  if (isPrimitive(c)) {
    childNodes.push(String(c))
  } else if (c instanceof VNode) {
    childNodes.push(c)
  } else if (isArray(c)) {
    for (var i = 0; i < c.length; i++) {
      addChild(c[i], childNodes, tag, props)
    }
  } else {
    throw Error(`${c} is a unexpected virtual dom node`)
  }
}

// 规范化传入的标签名
function normalizeTag (tag) {
  return delBlank(tag.toUpperCase())
}

// 规范化传入的属性
function normalizeProps (props) {
  for (var key in props) {
    var value = props[key]
    if (isPrimitive(value)) {
      props[key] = delBlank(String(value))
    }
  }
  return props
}

// 去除字符串多余空格，并将内部的多个空格转化为一个空格
function delBlank (str) {
  var regEx = /\s+/g
  return str.trim().replace(regEx, ' ')
}

export default h