Update types.

externs/closure-types.js

@@ -1412,4 +1412,22 @@ Polymer_DisableUpgradeMixin.prototype.connectedCallback = function(){};
 /**
 * @override
 */
-Polymer_DisableUpgradeMixin.prototype.disconnectedCallback = function(){};
+Polymer_DisableUpgradeMixin.prototype.disconnectedCallback = function(){};
+/**
+* @interface
+*/
+function Polymer_LegacyDataMixin(){}
+/**
+* @param {string} property Property that should trigger the effect
+* @param {string} type Effect type, from this.PROPERTY_EFFECT_TYPES
+* @param {Object=} effect Effect metadata object
+* @return {void}
+*/
+Polymer_LegacyDataMixin.prototype._addPropertyEffect = function(property, type, effect){};
+/**
+* @param {Object} templateInfo Template metadata to add effect to
+* @param {string} prop Property that should trigger the effect
+* @param {Object=} effect Effect metadata object
+* @return {void}
+*/
+Polymer_LegacyDataMixin._addTemplatePropertyEffect = function(templateInfo, prop, effect){};

types/lib/legacy/legacy-data-mixin.d.ts

@@ -9,21 +9,56 @@
  */
 
 /// <reference path="class.d.ts" />
+/// <reference path="../polymer.d.ts" />
 /// <reference path="../utils/mixin.d.ts" />
 
-declare class UndefinedArgumentError {
-  constructor(message: any);
+declare class UndefinedArgumentError extends Error {
+  constructor(message: any, arg: any);
 }
 
-declare class LegacyDataMixin {
+declare namespace Polymer {
+
 
   /**
-   * Overrides `Polyer.PropertyEffects` to wrap effect functions to
-   * catch `UndefinedArgumentError`s and warn.
+   * Mixin to selectively add back Polymer 1.x's `undefined` rules
+   * governing when observers & computing functions run based
+   * on all arguments being defined (reference https://www.polymer-project.org/1.0/docs/devguide/observers#multi-property-observers).
+   *
+   * When loaded, all legacy elements (defined with `Polymer({...})`)
+   * will have the mixin applied. The mixin only restores legacy data handling
+   * if `_legacyUndefinedCheck: true` is set on the element's prototype.
    *
-   * @param property Property that should trigger the effect
-   * @param type Effect type, from this.PROPERTY_EFFECT_TYPES
-   * @param effect Effect metadata object
+   * This mixin is intended for use to help migration from Polymer 1.x to
+   * 2.x+ by allowing legacy code to work while identifying observers and
+   * computing functions that need undefined checks to work without
+   * the mixin in Polymer 2.
    */
-  _addPropertyEffect(property: string, type: string, effect?: object|null): void;
+  function LegacyDataMixin<T extends new (...args: any[]) => {}>(base: T): T & LegacyDataMixinConstructor;
+
+  interface LegacyDataMixinConstructor {
+    new(...args: any[]): LegacyDataMixin;
+
+    /**
+     * Overrides `Polyer.PropertyEffects` to wrap effect functions to
+     * catch `UndefinedArgumentError`s and warn.
+     *
+     * @param templateInfo Template metadata to add effect to
+     * @param prop Property that should trigger the effect
+     * @param effect Effect metadata object
+     */
+    _addTemplatePropertyEffect(templateInfo: object|null, prop: string, effect?: object|null): void;
+  }
+
+  interface LegacyDataMixin {
+
+    /**
+     * Overrides `Polyer.PropertyEffects` to wrap effect functions to
+     * catch `UndefinedArgumentError`s and warn.
+     *
+     * @param property Property that should trigger the effect
+     * @param type Effect type, from this.PROPERTY_EFFECT_TYPES
+     * @param effect Effect metadata object
+     */
+    _addPropertyEffect(property: string, type: string, effect?: object|null): void;
+  }
 }