wasm-metering/demo/node_modules/bel/appendChild.js

injects metering into webassembly binaries

var trailingNewlineRegex = /\n[\s]+$/
var leadingNewlineRegex = /^\n[\s]+/
var trailingSpaceRegex = /[\s]+$/
var leadingSpaceRegex = /^[\s]+/
var multiSpaceRegex = /[\n\s]+/g

var TEXT_TAGS = [
  'a', 'abbr', 'b', 'bdi', 'bdo', 'br', 'cite', 'data', 'dfn', 'em', 'i',
  'kbd', 'mark', 'q', 'rp', 'rt', 'rtc', 'ruby', 's', 'amp', 'small', 'span',
  'strong', 'sub', 'sup', 'time', 'u', 'var', 'wbr'
]

var VERBATIM_TAGS = [
  'code', 'pre', 'textarea'
]

module.exports = function appendChild (el, childs) {
  if (!Array.isArray(childs)) return

  var nodeName = el.nodeName.toLowerCase()

  var hadText = false
  var value, leader

  for (var i = 0, len = childs.length; i < len; i++) {
    var node = childs[i]
    if (Array.isArray(node)) {
      appendChild(el, node)
      continue
    }

    if (typeof node === 'number' ||
      typeof node === 'boolean' ||
      typeof node === 'function' ||
      node instanceof Date ||
      node instanceof RegExp) {
      node = node.toString()
    }

    var lastChild = el.childNodes[el.childNodes.length - 1]

    // Iterate over text nodes
    if (typeof node === 'string') {
      hadText = true

      // If we already had text, append to the existing text
      if (lastChild && lastChild.nodeName === '#text') {
        lastChild.nodeValue += node

      // We didn't have a text node yet, create one
      } else {
        node = document.createTextNode(node)
        el.appendChild(node)
        lastChild = node
      }

      // If this is the last of the child nodes, make sure we close it out
      // right
      if (i === len - 1) {
        hadText = false
        // Trim the child text nodes if the current node isn't a
        // node where whitespace matters.
        if (TEXT_TAGS.indexOf(nodeName) === -1 &&
          VERBATIM_TAGS.indexOf(nodeName) === -1) {
          value = lastChild.nodeValue
            .replace(leadingNewlineRegex, '')
            .replace(trailingSpaceRegex, '')
            .replace(trailingNewlineRegex, '')
            .replace(multiSpaceRegex, ' ')
          if (value === '') {
            el.removeChild(lastChild)
          } else {
            lastChild.nodeValue = value
          }
        } else if (VERBATIM_TAGS.indexOf(nodeName) === -1) {
          // The very first node in the list should not have leading
          // whitespace. Sibling text nodes should have whitespace if there
          // was any.
          leader = i === 0 ? '' : ' '
          value = lastChild.nodeValue
            .replace(leadingNewlineRegex, leader)
            .replace(leadingSpaceRegex, ' ')
            .replace(trailingSpaceRegex, '')
            .replace(trailingNewlineRegex, '')
            .replace(multiSpaceRegex, ' ')
          lastChild.nodeValue = value
        }
      }

    // Iterate over DOM nodes
    } else if (node && node.nodeType) {
      // If the last node was a text node, make sure it is properly closed out
      if (hadText) {
        hadText = false

        // Trim the child text nodes if the current node isn't a
        // text node or a code node
        if (TEXT_TAGS.indexOf(nodeName) === -1 &&
          VERBATIM_TAGS.indexOf(nodeName) === -1) {
          value = lastChild.nodeValue
            .replace(leadingNewlineRegex, '')
            .replace(trailingNewlineRegex, '')
            .replace(multiSpaceRegex, ' ')

          // Remove empty text nodes, append otherwise
          if (value === '') {
            el.removeChild(lastChild)
          } else {
            lastChild.nodeValue = value
          }
        // Trim the child nodes if the current node is not a node
        // where all whitespace must be preserved
        } else if (VERBATIM_TAGS.indexOf(nodeName) === -1) {
          value = lastChild.nodeValue
            .replace(leadingSpaceRegex, ' ')
            .replace(leadingNewlineRegex, '')
            .replace(trailingNewlineRegex, '')
            .replace(multiSpaceRegex, ' ')
          lastChild.nodeValue = value
        }
      }

      // Store the last nodename
      var _nodeName = node.nodeName
      if (_nodeName) nodeName = _nodeName.toLowerCase()

      // Append the node to the DOM
      el.appendChild(node)
    }
  }
}