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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 { __extends, __read, __spreadArray, __values } from "tslib";
- import { getDescriptor } from './observer';
- /**
- * 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) {
- var _a, _b;
- if (baseClass === void 0) { baseClass = /** @class */ (function () {
- function class_1() {
- }
- return class_1;
- }()); }
- var unobserves = Symbol();
- return _b = /** @class */ (function (_super) {
- __extends(MDCObserver, _super);
- function MDCObserver() {
- var _this = _super !== null && _super.apply(this, arguments) || this;
- _this[_a] = [];
- return _this;
- }
- MDCObserver.prototype.observe = function (target, observers) {
- var e_1, _b;
- var _this = this;
- var cleanup = [];
- try {
- for (var _c = __values(Object.keys(observers)), _d = _c.next(); !_d.done; _d = _c.next()) {
- var property = _d.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 (_d && !_d.done && (_b = _c.return)) _b.call(_c);
- }
- finally { if (e_1) throw e_1.error; }
- }
- var unobserve = function () {
- var e_2, _b;
- 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 && (_b = cleanup_1.return)) _b.call(cleanup_1);
- }
- finally { if (e_2) throw e_2.error; }
- }
- var index = _this[unobserves].indexOf(unobserve);
- if (index > -1) {
- _this[unobserves].splice(index, 1);
- }
- };
- this[unobserves].push(unobserve);
- return unobserve;
- };
- MDCObserver.prototype.setObserversEnabled = function (target, enabled) {
- setObserversEnabled(target, enabled);
- };
- MDCObserver.prototype.unobserve = function () {
- var e_3, _b;
- try {
- // Iterate over a copy since unobserve() will remove themselves from the
- // array
- for (var _c = __values(__spreadArray([], __read(this[unobserves]))), _d = _c.next(); !_d.done; _d = _c.next()) {
- var unobserve = _d.value;
- unobserve();
- }
- }
- catch (e_3_1) { e_3 = { error: e_3_1 }; }
- finally {
- try {
- if (_d && !_d.done && (_b = _c.return)) _b.call(_c);
- }
- finally { if (e_3) throw e_3.error; }
- }
- };
- return MDCObserver;
- }(baseClass)),
- _a = unobserves,
- _b;
- }
- var isTargetObservers = Symbol();
- var isEnabled = Symbol();
- var getObservers = Symbol();
- /**
- * 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 observerPrototype = installObserver(target);
- var observers = observerPrototype[getObservers](property);
- observers.push(observer);
- return function () {
- observers.splice(observers.indexOf(observer), 1);
- };
- }
- /**
- * Installs a `TargetObservers` for the provided target (if not already
- * installed).
- *
- * A target's `TargetObservers` is installed as a Proxy on the target's
- * prototype.
- *
- * @template T The observed target type.
- * @param target - The target to observe.
- * @return The installed `TargetObservers` for the provided target.
- */
- function installObserver(target) {
- var e_4, _a, e_5, _b;
- var prototype = Object.getPrototypeOf(target);
- if (prototype[isTargetObservers]) {
- return prototype;
- }
- // Proxy prototypes will not trap plain properties (not a getter/setter) that
- // are already defined. They only work on new plain properties.
- // We can work around this by deleting the properties, installing the Proxy,
- // then re-setting the properties.
- var existingKeyValues = new Map();
- var keys = Object.getOwnPropertyNames(target);
- try {
- for (var keys_1 = __values(keys), keys_1_1 = keys_1.next(); !keys_1_1.done; keys_1_1 = keys_1.next()) {
- var key = keys_1_1.value;
- var descriptor = getDescriptor(target, key);
- if (descriptor && descriptor.writable) {
- existingKeyValues.set(key, descriptor.value);
- delete target[key];
- }
- }
- }
- catch (e_4_1) { e_4 = { error: e_4_1 }; }
- finally {
- try {
- if (keys_1_1 && !keys_1_1.done && (_a = keys_1.return)) _a.call(keys_1);
- }
- finally { if (e_4) throw e_4.error; }
- }
- var proxy = new Proxy(Object.create(prototype), {
- get: function (target, key, receiver) {
- return Reflect.get(target, key, receiver);
- },
- set: function (target, key, newValue, receiver) {
- var e_6, _a;
- var isTargetObserversKey = key === isTargetObservers ||
- key === isEnabled || key === getObservers;
- var previous = Reflect.get(target, key, receiver);
- // Do not use receiver when setting the target's key. We do not want
- // to change whatever the target's inherent receiver is.
- Reflect.set(target, key, newValue);
- if (!isTargetObserversKey && proxy[isEnabled] &&
- newValue !== previous) {
- try {
- for (var _b = __values(proxy[getObservers](key)), _c = _b.next(); !_c.done; _c = _b.next()) {
- var observer = _c.value;
- observer(newValue, previous);
- }
- }
- catch (e_6_1) { e_6 = { error: e_6_1 }; }
- finally {
- try {
- if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
- }
- finally { if (e_6) throw e_6.error; }
- }
- }
- return true;
- }
- });
- proxy[isTargetObservers] = true;
- proxy[isEnabled] = true;
- var observersMap = new Map();
- proxy[getObservers] = function (key) {
- var observers = observersMap.get(key) || [];
- if (!observersMap.has(key)) {
- observersMap.set(key, observers);
- }
- return observers;
- };
- Object.setPrototypeOf(target, proxy);
- try {
- // Re-set plain pre-existing properties so that the Proxy can trap them
- for (var _c = __values(existingKeyValues.entries()), _d = _c.next(); !_d.done; _d = _c.next()) {
- var _e = __read(_d.value, 2), key = _e[0], value = _e[1];
- target[key] = value;
- }
- }
- catch (e_5_1) { e_5 = { error: e_5_1 }; }
- finally {
- try {
- if (_d && !_d.done && (_b = _c.return)) _b.call(_c);
- }
- finally { if (e_5) throw e_5.error; }
- }
- return proxy;
- }
- /**
- * 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 prototype = Object.getPrototypeOf(target);
- if (prototype[isTargetObservers]) {
- prototype[isEnabled] = enabled;
- }
- }
- //# sourceMappingURL=observer-proxy.js.map
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