@danielkalen/simplybind/comparison/dist/bower_components/aurelia-binding/src/array-observation.js

Magically simple, framework-less one-way/two-way data binding for frontend/backend in ~5kb.

/* eslint-disable no-extend-native */
import {ModifyCollectionObserver} from './collection-observation';

let pop = Array.prototype.pop;
let push = Array.prototype.push;
let reverse = Array.prototype.reverse;
let shift = Array.prototype.shift;
let sort = Array.prototype.sort;
let splice = Array.prototype.splice;
let unshift = Array.prototype.unshift;

Array.prototype.pop = function() {
  let notEmpty = this.length > 0;
  let methodCallResult = pop.apply(this, arguments);
  if (notEmpty && this.__array_observer__ !== undefined) {
    this.__array_observer__.addChangeRecord({
      type: 'delete',
      object: this,
      name: this.length,
      oldValue: methodCallResult
    });
  }
  return methodCallResult;
};

Array.prototype.push = function() {
  let methodCallResult = push.apply(this, arguments);
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.addChangeRecord({
      type: 'splice',
      object: this,
      index: this.length - arguments.length,
      removed: [],
      addedCount: arguments.length
    });
  }
  return methodCallResult;
};

Array.prototype.reverse = function() {
  let oldArray;
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.flushChangeRecords();
    oldArray = this.slice();
  }
  let methodCallResult = reverse.apply(this, arguments);
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.reset(oldArray);
  }
  return methodCallResult;
};

Array.prototype.shift = function() {
  let notEmpty = this.length > 0;
  let methodCallResult = shift.apply(this, arguments);
  if (notEmpty && this.__array_observer__ !== undefined) {
    this.__array_observer__.addChangeRecord({
      type: 'delete',
      object: this,
      name: 0,
      oldValue: methodCallResult
    });
  }
  return methodCallResult;
};

Array.prototype.sort = function() {
  let oldArray;
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.flushChangeRecords();
    oldArray = this.slice();
  }
  let methodCallResult = sort.apply(this, arguments);
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.reset(oldArray);
  }
  return methodCallResult;
};

Array.prototype.splice = function() {
  let methodCallResult = splice.apply(this, arguments);
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.addChangeRecord({
      type: 'splice',
      object: this,
      index: arguments[0],
      removed: methodCallResult,
      addedCount: arguments.length > 2 ? arguments.length - 2 : 0
    });
  }
  return methodCallResult;
};

Array.prototype.unshift = function() {
  let methodCallResult = unshift.apply(this, arguments);
  if (this.__array_observer__ !== undefined) {
    this.__array_observer__.addChangeRecord({
      type: 'splice',
      object: this,
      index: 0,
      removed: [],
      addedCount: arguments.length
    });
  }
  return methodCallResult;
};

export function getArrayObserver(taskQueue, array) {
  return ModifyArrayObserver.for(taskQueue, array);
}

class ModifyArrayObserver extends ModifyCollectionObserver {
  constructor(taskQueue, array) {
    super(taskQueue, array);
  }

  /**
   * Searches for observer or creates a new one associated with given array instance
   * @param taskQueue
   * @param array instance for which observer is searched
   * @returns ModifyArrayObserver always the same instance for any given array instance
   */
  static for(taskQueue, array) {
    if (!('__array_observer__' in array)) {
      Reflect.defineProperty(array, '__array_observer__', {
        value: ModifyArrayObserver.create(taskQueue, array),
        enumerable: false, configurable: false
      });
    }
    return array.__array_observer__;
  }

  static create(taskQueue, array) {
    return new ModifyArrayObserver(taskQueue, array);
  }
}