wasm-metering/demo/node_modules/nanohtml/lib/server.js

injects metering into webassembly binaries

var BOOL_PROPS = require('./bool-props')

var boolPropRx = new RegExp('(' + BOOL_PROPS.join('|') + ')=["\']?$', 'i')

module.exports = nanothtmlServer

function nanothtmlServer (src, filename, options, done) {
  if (typeof src === 'string' && !/\n/.test(src) && filename && filename._flags) {
    var args = Array.prototype.slice.apply(arguments)
    return require('./browserify-transform.js').apply(this, args)
  }
  if (typeof src === 'object' && src && src.types && src.template) {
    return require('./babel').apply(this, arguments)
  }

  var boolMatch
  var pieces = arguments[0]
  var output = ''
  for (var i = 0; i < pieces.length; i++) {
    var piece = pieces[i]
    if (i < pieces.length - 1) {
      if ((boolMatch = boolPropRx.exec(piece))) {
        output += piece.slice(0, boolMatch.index)
        if (arguments[i + 1]) {
          output += boolMatch[1] + '="' + boolMatch[1] + '"'
        }
        continue
      }

      var value = handleValue(arguments[i + 1])
      if (piece[piece.length - 1] === '=') {
        output += piece + '"' + value + '"'
      } else {
        output += piece + value
      }
    } else {
      output += piece
    }
  }

  // HACK: Avoid double encoding by marking encoded string
  // You cannot add properties to string literals
  // eslint-disable-next-line no-new-wrappers
  var wrapper = new String(output)
  wrapper.__encoded = true
  return wrapper
}

function handleValue (value) {
  // Suppose that each item is a result of html``.
  if (Array.isArray(value)) return value.join('')

  // Ignore event handlers. `onclick=${(e) => doSomething(e)}`
  // will become.           `onclick=""`
  if (typeof value === 'function') return ''
  if (value === null || value === undefined) return ''
  if (value.__encoded) return value

  if (typeof value === 'object') {
    return Object.keys(value).reduce(function (str, key, i) {
      if (str.length > 0) str += ' '

      if (BOOL_PROPS.indexOf(key) !== -1) {
        if (value[key]) {
          return str + key + '="' + key + '"'
        }
        return str
      }

      var handled = handleValue(value[key])
      return str + key + '="' + handled + '"'
    }, '')
  }

  var str = value.toString()
  return str
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#039;')
}