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- /**
- * @license
- * Copyright 2021 Google Inc.
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
- import { __assign, __extends, __read, __spreadArray, __values } from "tslib";
- /**
- * Mixin to add `MDCObserver` functionality to an optional base class.
- *
- * @deprecated Prefer MDCObserverFoundation for stricter closure compliance.
- * @template C Optional base class constructor type.
- * @param baseClass - Optional base class.
- * @return A class that extends the optional base class with `MDCObserver`
- * functionality.
- */
- export function mdcObserver(baseClass) {
- if (baseClass === void 0) { baseClass = /** @class */ (function () {
- function class_1() {
- }
- return class_1;
- }()); }
- // Mixin classes cannot use private members and Symbol() cannot be used in 3P
- // for IE11.
- var unobserveMap = new WeakMap();
- return /** @class */ (function (_super) {
- __extends(MDCObserver, _super);
- function MDCObserver() {
- return _super !== null && _super.apply(this, arguments) || this;
- }
- MDCObserver.prototype.observe = function (target, observers) {
- var e_1, _a;
- var _this = this;
- var cleanup = [];
- try {
- for (var _b = __values(Object.keys(observers)), _c = _b.next(); !_c.done; _c = _b.next()) {
- var property = _c.value;
- var observer = observers[property].bind(this);
- cleanup.push(observeProperty(target, property, observer));
- }
- }
- catch (e_1_1) { e_1 = { error: e_1_1 }; }
- finally {
- try {
- if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
- }
- finally { if (e_1) throw e_1.error; }
- }
- var unobserve = function () {
- var e_2, _a;
- try {
- for (var cleanup_1 = __values(cleanup), cleanup_1_1 = cleanup_1.next(); !cleanup_1_1.done; cleanup_1_1 = cleanup_1.next()) {
- var cleanupFn = cleanup_1_1.value;
- cleanupFn();
- }
- }
- catch (e_2_1) { e_2 = { error: e_2_1 }; }
- finally {
- try {
- if (cleanup_1_1 && !cleanup_1_1.done && (_a = cleanup_1.return)) _a.call(cleanup_1);
- }
- finally { if (e_2) throw e_2.error; }
- }
- var unobserves = unobserveMap.get(_this) || [];
- var index = unobserves.indexOf(unobserve);
- if (index > -1) {
- unobserves.splice(index, 1);
- }
- };
- var unobserves = unobserveMap.get(this);
- if (!unobserves) {
- unobserves = [];
- unobserveMap.set(this, unobserves);
- }
- unobserves.push(unobserve);
- return unobserve;
- };
- MDCObserver.prototype.setObserversEnabled = function (target, enabled) {
- setObserversEnabled(target, enabled);
- };
- MDCObserver.prototype.unobserve = function () {
- var e_3, _a;
- // Iterate over a copy since unobserve() will remove themselves from the
- // array
- var unobserves = unobserveMap.get(this) || [];
- try {
- for (var _b = __values(__spreadArray([], __read(unobserves))), _c = _b.next(); !_c.done; _c = _b.next()) {
- var unobserve = _c.value;
- unobserve();
- }
- }
- catch (e_3_1) { e_3 = { error: e_3_1 }; }
- finally {
- try {
- if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
- }
- finally { if (e_3) throw e_3.error; }
- }
- };
- return MDCObserver;
- }(baseClass));
- }
- /**
- * Observe a target's property for changes. When a property changes, the
- * provided `Observer` function will be invoked with the properties current and
- * previous values.
- *
- * The returned cleanup function will stop listening to changes for the
- * provided `Observer`.
- *
- * @template T The observed target type.
- * @template K The observed property.
- * @param target - The target to observe.
- * @param property - The property of the target to observe.
- * @param observer - An observer function to invoke each time the property
- * changes.
- * @return A cleanup function that will stop observing changes for the provided
- * `Observer`.
- */
- export function observeProperty(target, property, observer) {
- var targetObservers = installObserver(target, property);
- var observers = targetObservers.getObservers(property);
- observers.push(observer);
- return function () {
- observers.splice(observers.indexOf(observer), 1);
- };
- }
- /**
- * A Map of all `TargetObservers` that have been installed.
- */
- var allTargetObservers = new WeakMap();
- /**
- * Installs a `TargetObservers` for the provided target (if not already
- * installed), and replaces the given property with a getter and setter that
- * will respond to changes and call `TargetObservers`.
- *
- * Subsequent calls to `installObserver()` with the same target and property
- * will not override the property's previously installed getter/setter.
- *
- * @template T The observed target type.
- * @template K The observed property to create a getter/setter for.
- * @param target - The target to observe.
- * @param property - The property to create a getter/setter for, if needed.
- * @return The installed `TargetObservers` for the provided target.
- */
- function installObserver(target, property) {
- var observersMap = new Map();
- if (!allTargetObservers.has(target)) {
- allTargetObservers.set(target, {
- isEnabled: true,
- getObservers: function (key) {
- var observers = observersMap.get(key) || [];
- if (!observersMap.has(key)) {
- observersMap.set(key, observers);
- }
- return observers;
- },
- installedProperties: new Set()
- });
- }
- var targetObservers = allTargetObservers.get(target);
- if (targetObservers.installedProperties.has(property)) {
- // The getter/setter has already been replaced for this property
- return targetObservers;
- }
- // Retrieve (or create if it's a plain property) the original descriptor from
- // the target...
- var descriptor = getDescriptor(target, property) || {
- configurable: true,
- enumerable: true,
- value: target[property],
- writable: true
- };
- // ...and create a copy that will be used for the observer.
- var observedDescriptor = __assign({}, descriptor);
- var descGet = descriptor.get, descSet = descriptor.set;
- if ('value' in descriptor) {
- // The descriptor is a simple value (not a getter/setter).
- // For our observer descriptor that we copied, delete the value/writable
- // properties, since they are incompatible with the get/set properties
- // for descriptors.
- delete observedDescriptor.value;
- delete observedDescriptor.writable;
- // Set up a simple getter...
- var value_1 = descriptor.value;
- descGet = function () { return value_1; };
- // ...and setter (if the original property was writable).
- if (descriptor.writable) {
- descSet = function (newValue) {
- value_1 = newValue;
- };
- }
- }
- if (descGet) {
- observedDescriptor.get = function () {
- // `this as T` needed for closure conformance
- // tslint:disable-next-line:no-unnecessary-type-assertion
- return descGet.call(this);
- };
- }
- if (descSet) {
- observedDescriptor.set = function (newValue) {
- var e_4, _a;
- // `thus as T` needed for closure conformance
- // tslint:disable-next-line:no-unnecessary-type-assertion
- var previous = descGet ? descGet.call(this) : newValue;
- // tslint:disable-next-line:no-unnecessary-type-assertion
- descSet.call(this, newValue);
- if (targetObservers.isEnabled && (!descGet || newValue !== previous)) {
- try {
- for (var _b = __values(targetObservers.getObservers(property)), _c = _b.next(); !_c.done; _c = _b.next()) {
- var observer = _c.value;
- observer(newValue, previous);
- }
- }
- catch (e_4_1) { e_4 = { error: e_4_1 }; }
- finally {
- try {
- if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
- }
- finally { if (e_4) throw e_4.error; }
- }
- }
- };
- }
- targetObservers.installedProperties.add(property);
- Object.defineProperty(target, property, observedDescriptor);
- return targetObservers;
- }
- /**
- * Retrieves the descriptor for a property from the provided target. This
- * function will walk up the target's prototype chain to search for the
- * descriptor.
- *
- * @template T The target type.
- * @template K The property type.
- * @param target - The target to retrieve a descriptor from.
- * @param property - The name of the property to retrieve a descriptor for.
- * @return the descriptor, or undefined if it does not exist. Keep in mind that
- * plain properties may not have a descriptor defined.
- */
- export function getDescriptor(target, property) {
- var descriptorTarget = target;
- var descriptor;
- while (descriptorTarget) {
- descriptor = Object.getOwnPropertyDescriptor(descriptorTarget, property);
- if (descriptor) {
- break;
- }
- // Walk up the instance's prototype chain in case the property is declared
- // on a superclass.
- descriptorTarget = Object.getPrototypeOf(descriptorTarget);
- }
- return descriptor;
- }
- /**
- * Enables or disables all observers for a provided target. Changes to observed
- * properties will not call any observers when disabled.
- *
- * @template T The observed target type.
- * @param target - The target to enable or disable observers for.
- * @param enabled - True to enable or false to disable observers.
- */
- export function setObserversEnabled(target, enabled) {
- var targetObservers = allTargetObservers.get(target);
- if (targetObservers) {
- targetObservers.isEnabled = enabled;
- }
- }
- //# sourceMappingURL=observer.js.map
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