jsonstore-js/lib/PathListener.js

A javascript JSON data store with manifold abilities of data processing

'use strict';

function PathListener(options) {
  options = options || {};
  this.deepEqual = options.deepEqual === true;
  this.copyStore = options.copyStore;
  this.listenerTree = {};
  this.groupRefs = {};
  this.store = options.store || {};
  this.flashKeys = options.flashKeys || {};
}

PathListener.prototype = {
  _copyData: function _copyData(data) {
    if (data === undefined) return data;
    return this.copyStore ? JSON.parse(JSON.stringify(data)) : data;
  },
  _removeListener: function _removeListener(listeners, cb) {
    var index = listeners.indexOf(cb);
    index > -1 && (listeners[index] = null);
    return index;
  },
  registerListener: function registerListener(path, cb, group, check) {
    group = typeof group === 'string' ? group : null;
    check = group === null ? group !== false : check !== false;
    var i = 0,
        len = path.length,
        pathItem = void 0,
        treeRef = this.listenerTree,
        listenerIndex = void 0;
    while (i < len) {
      pathItem = path[i++];
      if (treeRef[pathItem] === undefined) {
        treeRef[pathItem] = { children: {}, listeners: [] };
      }
      treeRef = i === len ? treeRef[pathItem] : treeRef[pathItem].children;
    }
    listenerIndex = treeRef.listeners.indexOf(cb);
    listenerIndex = listenerIndex === -1 ? treeRef.listeners.push(cb) - 1 : listenerIndex;
    if (group !== null) {
      if (this.groupRefs[group] === undefined) {
        this.groupRefs[group] = [];
      }
      this.groupRefs[group].push([treeRef.listeners, listenerIndex]);
    }
    if (check) {
      this.checkPath(path);
    }
  },
  checkPath: function checkPath(path) {
    var _this = this;

    var i = 0,
        len = path.length,
        pathItem = void 0,
        treeRef = this.listenerTree,
        dataRef = this.store;
    while (i < len) {
      if (dataRef === undefined) break;
      pathItem = path[i++];
      dataRef = dataRef[pathItem];
      if (treeRef[pathItem] !== undefined) {
        treeRef[pathItem].listeners.forEach(function (listener) {
          typeof listener === 'function' && listener(_this._copyData(dataRef));
        });
      } else {
        break;
      }
      treeRef = treeRef[pathItem].children;
    }
    if (path.length === 1 && this.flashKeys[path[0]]) {
      this.store[path[0]] = null;
    }
  },
  removeAllListeners: function removeAllListeners() {
    this.listenerTree = {};
    this.groupRefs = {};
  },
  removeListenerByPath: function removeListenerByPath(path, cb) {
    if (typeof cb !== 'function') return void 0;
    var i = 0,
        len = path.length,
        pathItem = void 0,
        treeRef = this.listenerTree;
    while (i < len) {
      pathItem = path[i++];
      if (treeRef[pathItem] === undefined) {
        return void 0;
      }
      treeRef = i === len ? treeRef[pathItem] : treeRef[pathItem].children;
    }
    this._removeListener(treeRef.listeners, cb);
  },
  removeListenerByGroup: function removeListenerByGroup(group) {
    var groupListeners = this.groupRefs[group];
    if (groupListeners !== undefined) {
      groupListeners.forEach(function (pair) {
        typeof pair[0][pair[1]] === 'function' && (pair[0][pair[1]] = null);
      });
    }
  }
};

module.exports = PathListener;