@material/base
Version:
The set of base classes for Material Components for the web
256 lines • 10.4 kB
JavaScript
/**
* @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;
}
}
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