handsontable/3rdparty/walkontable/src/utils/orderView/rendererAdapter/differBasedRendererAdapter.js

Handsontable is a JavaScript Data Grid available for React, Angular and Vue.

"use strict";

exports.__esModule = true;
function _defineProperty(e, r, t) { return (r = _toPropertyKey(r)) in e ? Object.defineProperty(e, r, { value: t, enumerable: !0, configurable: !0, writable: !0 }) : e[r] = t, e; }
function _toPropertyKey(t) { var i = _toPrimitive(t, "string"); return "symbol" == typeof i ? i : i + ""; }
function _toPrimitive(t, r) { if ("object" != typeof t || !t) return t; var e = t[Symbol.toPrimitive]; if (void 0 !== e) { var i = e.call(t, r || "default"); if ("object" != typeof i) return i; throw new TypeError("@@toPrimitive must return a primitive value."); } return ("string" === r ? String : Number)(t); }
/**
 * Differ based renderer adapter that uses ViewDiffer for efficient DOM manipulation.
 * This is the default implementation for most browsers.
 *
 * @class {DifferBasedRendererAdapter}
 */
class DifferBasedRendererAdapter {
  /**
   * @param {OrderView} orderView The OrderView instance.
   */
  constructor(orderView) {
    /**
     * The list of render commands to execute. The command is an array with the following
     * structure: [
     *   [
     *     'prepend' | 'append' | 'insert_before' | 'replace' | 'remove', // command name
     *     10, // processed node index
     *     9,  // previous node index (only for 'insert_before' and 'replace' commands)
     *     8   // node index to remove (only for 'insert_before' command)
     *   ],
     *   ...
     * ].
     *
     * @type {Array[]}
     */
    _defineProperty(this, "leads", []);
    this.orderView = orderView;
  }

  /**
   * Applies the commands generated by the differ into the specific DOM operations.
   *
   * @param {Array} command The command to apply.
   */
  applyCommand(command) {
    const {
      rootNode
    } = this.orderView;
    const [name, nodeIndex, nodePrevIndex, nodeIndexToRemove] = command;
    const node = this.orderView.nodesPool(nodeIndex);
    this.orderView.collectedNodes.push(node);
    switch (name) {
      case 'prepend':
        rootNode.insertBefore(node, rootNode.firstChild);
        break;
      case 'append':
        rootNode.appendChild(node);
        break;
      case 'insert_before':
        rootNode.insertBefore(node, this.orderView.nodesPool(nodePrevIndex));
        // To keep the constant length of child nodes (after inserting a node) remove the last child.
        rootNode.removeChild(this.orderView.nodesPool(nodeIndexToRemove));
        break;
      case 'replace':
        rootNode.replaceChild(node, this.orderView.nodesPool(nodePrevIndex));
        break;
      case 'remove':
        rootNode.removeChild(node);
        break;
      default:
        break;
    }
  }

  /**
   * Sets up and prepares all necessary properties and starts the rendering process.
   * This method has to be called only once (at the start) for the render cycle.
   */
  start() {
    this.orderView.collectedNodes.length = 0;
    this.leads = this.orderView.viewDiffer.diff();
  }

  /**
   * Renders the DOM element based on visual index (which is calculated internally).
   * This method has to be called as many times as the size count is met (to cover all previously rendered DOM elements).
   */
  render() {
    if (this.leads.length > 0) {
      this.applyCommand(this.leads.shift());
    }
  }

  /**
   * Ends the render process.
   * This method has to be called only once (at the end) for the render cycle.
   */
  end() {
    while (this.leads.length > 0) {
      this.applyCommand(this.leads.shift());
    }
  }
}
exports.DifferBasedRendererAdapter = DifferBasedRendererAdapter;