dev/js/src/menu/item.js

/*
 * MenuItems may define:
 *
 * onclick: action happen on click and enter.
 * further: action happen on right arrow
 */

"use strict";

/**
 * Item in the Dropdown menu
 */
define({
  /**
   * Create a new MenuItem object.
   *
   * @constructor
   * @this {MenuItem}
   * @param {Array.<string>} An array object of name, action and
   *   optionally a description
   */
  create : function (params) {
    return Object.create(this)._init(params);
  },


  /**
   * Upgrade this object to another object,
   * while private data stays intact.
   *
   * @param {Object] An object with properties.
   */
  upgradeTo : function (props) {
    for (let prop in props) {
      this[prop] = props[prop];
    };
    return this;
  },


  /**
   * Get or set the content of the meun item.
   */
  content : function (content) {
    if (arguments.length === 1)
      this._content = document.createTextNode(content);
    return this._content;
  },


  /**
   * Get or set the information for action of this item. 
   */
  action : function (action) {
    if (arguments.length === 1)
      this._action = action;
    return this._action;
  },
  

  /**
   * Get the lower cased field of the item
   * (used for analyses).
   */
  lcField : function () {
    return this._lcField;
  },


  /**
   * Check or set if the item is active
   *
   * @param {boolean|null} State of activity
   */
  active : function (bool) {
    const cl = this.element().classList;
    if (bool === undefined)
      return cl.contains("active");
    else if (bool)
      cl.add("active");
    else
      cl.remove("active");
  },


  /**
   * Check or set if the item is
   * at the boundary of the menu
   * list
   *
   * @param {boolean|null} State of activity
   */
  noMore : function (bool) {
    const cl = this.element().classList;
    if (bool === undefined)
      return cl.contains("no-more");
    else if (bool)
      cl.add("no-more");
    else
      cl.remove("no-more");
  },
  
  /**
   * Get the document element of the menu item
   */
  element : function () {
    // already defined
    if (this._element !== undefined)
      return this._element;
    
    // Create list item
    const li = document.createElement("li");

    // Connect action
    if (this["onclick"] !== undefined) {
      li["onclick"] = this.onclick.bind(this);
    };

    // Append template
    li.appendChild(this.content());
    
    return this._element = li;
  },

  /**
   * Highlight parts of the item
   *
   * @param {string} Prefix string for highlights
   */
  highlight : function (prefix) {

    // The prefix already matches
    if (this._prefix === prefix)
      return;

    // There is a prefix but it doesn't match
    if (this._prefix !== null) {
      this.lowlight();
    }

    const children = this.element().childNodes;
    for (let i = children.length -1; i >= 0; i--) {
      this._highlight(children[i], prefix);
    };

    this._prefix = prefix;
  },


  /**
   * Remove highlight of the menu item
   */
  lowlight : function () {
    if (this._prefix === null)
      return;

    const e = this.element();
    
    const marks = e.getElementsByTagName("mark");

    for (let i = marks.length - 1; i >= 0; i--) {

      // Replace with content
      marks[i].parentNode.replaceChild(
        // Create text node clone
	      document.createTextNode(
	        marks[i].firstChild.nodeValue
        ),
	      marks[i]
      );
    };

    // Remove consecutive textnodes
    e.normalize();
    this._prefix = null;
  },


  // Highlight a certain substring of the menu item
  _highlight : function (elem, prefixString) {    
    if (elem.nodeType === 3) {
      
      const text   = elem.nodeValue;
      const textlc = text.toLowerCase();

      // Split prefixes
      if (prefixString) {

        // ND:
        //   Doing this in a single line can trigger
        //   a deep-recursion in Firefox 57.01, though I don't know why.
        prefixString = prefixString.trim();

        const prefixes = prefixString.split(" ");

        let testPos,
            pos = -1,
            len = 0;

        // Iterate over all prefixes and get the best one
        // for (var i = 0; i < prefixes.length; i++) {
        prefixes.forEach(function(i) {

          // Get first pos of a matching prefix
          testPos = textlc.indexOf(i);
          if (testPos < 0)
            return;

          if (pos === -1 || testPos < pos) {
            pos = testPos;
            len = i.length;
          }
          else if (testPos === pos && i.length > len) {
            len = i.length;
          };
        });

        // Matches!
        if (pos >= 0) {
	
	        // First element
	        if (pos > 0) {
	          elem.parentNode.insertBefore(
	            document.createTextNode(text.substr(0, pos)),
	            elem
	          );
	        };
	
	        // Second element
	        const hl = document.createElement("mark");
	        hl.appendChild(
	          document.createTextNode(text.substr(pos, len))
	        );
	        elem.parentNode.insertBefore(hl, elem);
	
	        // Third element
	        const third = text.substr(pos + len);

	        if (third.length > 0) {
	          const thirdE = document.createTextNode(third);
	          elem.parentNode.insertBefore(
	            thirdE,
	            elem
	          );
	          this._highlight(thirdE, prefixString);
	        };
	
          elem.parentNode.removeChild(elem);
        };
      };
    }

    else {
      const children = elem.childNodes;
      for (let i = children.length -1; i >= 0; i--) {
	      this._highlight(children[i], prefixString);
      };
    };
  },

  // Initialize menu item
  _init : function (params) {
    
    if (params[0] === undefined) {
      throw new Error("Missing parameters");
    };

    const t = this;

    t.content(params[0]);
    
    if (params.length > 1) {
      t._action = params[1];

      if (params.length > 2)
        t._onclick = params[2];
    };
    
    t._lcField = ' ' + t.content().textContent.toLowerCase();
    t._prefix = null;

    return this;
  },


  /**
   * The click action of the menu item.
   */
  onclick : function (e) {
    const m = this.menu();

    // Reset prefix
    m.prefix("");

    if (this._onclick)
      this._onclick.apply(this, e);

    m.hide();
  },

  
  /**
   * Return menu list.
   */
  menu : function () {
    return this._menu;
  }
});