mutable-data-behavior.d.ts

/**
 * DO NOT EDIT
 *
 * This file was automatically generated by
 *   https://github.com/Polymer/gen-typescript-declarations
 *
 * To modify these typings, edit the source file(s):
 *   lib/legacy/mutable-data-behavior.html
 */

/// <reference path="../mixins/mutable-data.d.ts" />

declare namespace Polymer {

  /**
   * Legacy element behavior to skip strict dirty-checking for objects and arrays,
   * (always consider them to be "dirty") for use on legacy API Polymer elements.
   *
   * By default, `Polymer.PropertyEffects` performs strict dirty checking on
   * objects, which means that any deep modifications to an object or array will
   * not be propagated unless "immutable" data patterns are used (i.e. all object
   * references from the root to the mutation were changed).
   *
   * Polymer also provides a proprietary data mutation and path notification API
   * (e.g. `notifyPath`, `set`, and array mutation API's) that allow efficient
   * mutation and notification of deep changes in an object graph to all elements
   * bound to the same object graph.
   *
   * In cases where neither immutable patterns nor the data mutation API can be
   * used, applying this mixin will cause Polymer to skip dirty checking for
   * objects and arrays (always consider them to be "dirty").  This allows a
   * user to make a deep modification to a bound object graph, and then either
   * simply re-set the object (e.g. `this.items = this.items`) or call `notifyPath`
   * (e.g. `this.notifyPath('items')`) to update the tree.  Note that all
   * elements that wish to be updated based on deep mutations must apply this
   * mixin or otherwise skip strict dirty checking for objects/arrays.
   * Specifically, any elements in the binding tree between the source of a
   * mutation and the consumption of it must apply this behavior or enable the
   * `Polymer.OptionalMutableDataBehavior`.
   *
   * In order to make the dirty check strategy configurable, see
   * `Polymer.OptionalMutableDataBehavior`.
   *
   * Note, the performance characteristics of propagating large object graphs
   * will be worse as opposed to using strict dirty checking with immutable
   * patterns or Polymer's path notification API.
   */
  interface MutableDataBehavior {

    /**
     * Overrides `Polymer.PropertyEffects` to provide option for skipping
     * strict equality checking for Objects and Arrays.
     *
     * This method pulls the value to dirty check against from the `__dataTemp`
     * cache (rather than the normal `__data` cache) for Objects.  Since the temp
     * cache is cleared at the end of a turn, this implementation allows
     * side-effects of deep object changes to be processed by re-setting the
     * same object (using the temp cache as an in-turn backstop to prevent
     * cycles due to 2-way notification).
     *
     * @param property Property name
     * @param value New property value
     * @param old Previous property value
     * @returns Whether the property should be considered a change
     */
    _shouldPropertyChange(property: string, value: any, old: any): boolean;
  }

  /**
   * Legacy element behavior to add the optional ability to skip strict
   * dirty-checking for objects and arrays (always consider them to be
   * "dirty") by setting a `mutable-data` attribute on an element instance.
   *
   * By default, `Polymer.PropertyEffects` performs strict dirty checking on
   * objects, which means that any deep modifications to an object or array will
   * not be propagated unless "immutable" data patterns are used (i.e. all object
   * references from the root to the mutation were changed).
   *
   * Polymer also provides a proprietary data mutation and path notification API
   * (e.g. `notifyPath`, `set`, and array mutation API's) that allow efficient
   * mutation and notification of deep changes in an object graph to all elements
   * bound to the same object graph.
   *
   * In cases where neither immutable patterns nor the data mutation API can be
   * used, applying this mixin will allow Polymer to skip dirty checking for
   * objects and arrays (always consider them to be "dirty").  This allows a
   * user to make a deep modification to a bound object graph, and then either
   * simply re-set the object (e.g. `this.items = this.items`) or call `notifyPath`
   * (e.g. `this.notifyPath('items')`) to update the tree.  Note that all
   * elements that wish to be updated based on deep mutations must apply this
   * mixin or otherwise skip strict dirty checking for objects/arrays.
   * Specifically, any elements in the binding tree between the source of a
   * mutation and the consumption of it must enable this behavior or apply the
   * `Polymer.OptionalMutableDataBehavior`.
   *
   * While this behavior adds the ability to forgo Object/Array dirty checking,
   * the `mutableData` flag defaults to false and must be set on the instance.
   *
   * Note, the performance characteristics of propagating large object graphs
   * will be worse by relying on `mutableData: true` as opposed to using
   * strict dirty checking with immutable patterns or Polymer's path notification
   * API.
   */
  interface OptionalMutableDataBehavior {

    /**
     * Instance-level flag for configuring the dirty-checking strategy
     * for this element.  When true, Objects and Arrays will skip dirty
     * checking, otherwise strict equality checking will be used.
     */
    mutableData: boolean|null|undefined;

    /**
     * Overrides `Polymer.PropertyEffects` to skip strict equality checking
     * for Objects and Arrays.
     *
     * Pulls the value to dirty check against from the `__dataTemp` cache
     * (rather than the normal `__data` cache) for Objects.  Since the temp
     * cache is cleared at the end of a turn, this implementation allows
     * side-effects of deep object changes to be processed by re-setting the
     * same object (using the temp cache as an in-turn backstop to prevent
     * cycles due to 2-way notification).
     *
     * @param property Property name
     * @param value New property value
     * @param old Previous property value
     * @returns Whether the property should be considered a change
     */
    _shouldPropertyChange(property: string, value: any, old: any): boolean;
  }
}