makestatic-parse-html/lib/adapter.js

Parses HTML files to an abstract syntax tree

/**
 *  Adapter for css-select so it ccan query the parse5 DOM tree.
 */
class DomAdapter {
  static isTag (elem) {
    return elem.tagName !== undefined
  }

  static getParent (elem) {
    return elem.parentNode
  }

  static getName (elem) {
    return elem.tagName
  }

  static getChildren (elem) {
    /* istanbul ignore next: guard against no child nodes */
    return elem.childNodes || []
  }

  static getText (elem, text = '') {
    const childs = DomAdapter.getChildren(elem)
    childs.forEach((node) => {
      if (DomAdapter.isTag(node)) {
        text += DomAdapter.getText(node, text)
      } else if (node.nodeName === '#text') {
        text += node.value
      }
    })

    return text
  }

  static getSiblings (elem) {
    const parent = DomAdapter.getParent(elem)
    return parent && DomAdapter.getChildren(parent)
  }

  static existsOne (test, nodes) {
    let node
    for (let i = 0; i < nodes.length; i++) {
      node = nodes[i]
      if (DomAdapter.isTag(node) &&
          (test(node) ||
          DomAdapter.existsOne(test, DomAdapter.getChildren(node)))) {
        return true
      }
    }
    return false
  }

  static getAttributeValue (elem, name) {
    let attr
    /* istanbul ignore next: guard against no attributes */
    let attrs = elem.attrs || []
    for (let i = 0; i < attrs.length; i++) {
      attr = attrs[i]
      if (attr.name === name) {
        return attr.value
      }
    }
  }

  static hasAttrib (elem, name) {
    return DomAdapter.getAttributeValue(elem, name) !== undefined
  }

  static findOne (test, nodes) {
    let childs, elem
    for (let i = 0; i < nodes.length; i++) {
      if (!DomAdapter.isTag(nodes[i])) {
        continue
      }
      if (test(nodes[i])) {
        return nodes[i]
      }
      childs = DomAdapter.getChildren(nodes[i])
      elem = DomAdapter.findAll(test, childs)
      if (elem.length) {
        return elem[0]
      }
    }
  }

  static findAll (test, nodes) {
    let result = []
    let childs
    for (let i = 0; i < nodes.length; i++) {
      if (!DomAdapter.isTag(nodes[i])) {
        continue
      }
      if (test(nodes[i])) {
        result.push(nodes[i])
      }
      childs = DomAdapter.getChildren(nodes[i])
      result = result.concat(DomAdapter.findAll(test, childs))
    }
    return result
  }

  /**
   *  Utility to get an attribute from a node.
   *
   *  Iterates the attribute list and gets the first attribute that has
   *  the given name and optionally a specific value.
   *
   *  Note this is an extension to the interface required by `css-select`.
   *
   *  @static {function} getAttribute
   *  @param {Object} el the node.
   *  @param {String} name the attribute name.
   *  @param {String} [value] the attribute value.
   *
   *  @returns the attribute or undefined.
   */
  static getAttribute (el, name, value) {
    const attrs = el.attrs
    if (!attrs) {
      return
    }
    let attr
    for (let i = 0; i < attrs.length; i++) {
      attr = attrs[i]
      if (attr.name === name) {
        if (value && attr.value === value) {
          return attr
        } else if (!value) {
          return attr
        }
      }
    }
  }

  static setAttributeValue (elem, name, value) {
    /* istanbul ignore next: guard against no attributes */
    let attrs = elem.attrs || []
    let attr = attrs.find((att) => {
      return att.name === name
    })
    if (attr) {
      attr.value = value
    } else {
      attrs.push({name: name, value: value})
    }
  }

  static createElement (tagName, attributes) {
    let attrs = []
    for (let k in attributes) {
      attrs.push({name: k, value: attributes[k]})
    }
    return {
      nodeName: tagName,
      tagName: tagName,
      attrs: attrs,
      namespaceURI: 'http://www.w3.org/1999/xhtml',
      childNodes: []
    }
  }

  static createTextNode (data) {
    return {nodeName: '#text', value: data}
  }

  static prependChild (parent, elem) {
    // TODO: remove from existing element if parentNode
    elem.parentNode = parent
    parent.childNodes.unshift(elem)
  }

  static appendChild (parent, elem) {
    // TODO: remove from existing element if parentNode
    elem.parentNode = parent
    parent.childNodes.push(elem)
  }
}

module.exports = DomAdapter