/** * @license * Copyright Google Inc. All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ /** * Suppress closure compiler errors about unknown 'global' variable * @fileoverview * @suppress {undefinedVars} */ /** * Zone is a mechanism for intercepting and keeping track of asynchronous work. * * A Zone is a global object which is configured with rules about how to intercept and keep track * of the asynchronous callbacks. Zone has these responsibilities: * * 1. Intercept asynchronous task scheduling * 2. Wrap callbacks for error-handling and zone tracking across async operations. * 3. Provide a way to attach data to zones * 4. Provide a context specific last frame error handling * 5. (Intercept blocking methods) * * A zone by itself does not do anything, instead it relies on some other code to route existing * platform API through it. (The zone library ships with code which monkey patches all of the * browsers's asynchronous API and redirects them through the zone for interception.) * * In its simplest form a zone allows one to intercept the scheduling and calling of asynchronous * operations, and execute additional code before as well as after the asynchronous task. The rules * of interception are configured using [ZoneConfig]. There can be many different zone instances in * a system, but only one zone is active at any given time which can be retrieved using * [Zone#current]. * * * * ## Callback Wrapping * * An important aspect of the zones is that they should persist across asynchronous operations. To * achieve this, when a future work is scheduled through async API, it is necessary to capture, and * subsequently restore the current zone. For example if a code is running in zone `b` and it * invokes `setTimeout` to scheduleTask work later, the `setTimeout` method needs to 1) capture the * current zone and 2) wrap the `wrapCallback` in code which will restore the current zone `b` once * the wrapCallback executes. In this way the rules which govern the current code are preserved in * all future asynchronous tasks. There could be a different zone `c` which has different rules and * is associated with different asynchronous tasks. As these tasks are processed, each asynchronous * wrapCallback correctly restores the correct zone, as well as preserves the zone for future * asynchronous callbacks. * * Example: Suppose a browser page consist of application code as well as third-party * advertisement code. (These two code bases are independent, developed by different mutually * unaware developers.) The application code may be interested in doing global error handling and * so it configures the `app` zone to send all of the errors to the server for analysis, and then * executes the application in the `app` zone. The advertising code is interested in the same * error processing but it needs to send the errors to a different third-party. So it creates the * `ads` zone with a different error handler. Now both advertising as well as application code * create many asynchronous operations, but the [Zone] will ensure that all of the asynchronous * operations created from the application code will execute in `app` zone with its error * handler and all of the advertisement code will execute in the `ads` zone with its error handler. * This will not only work for the async operations created directly, but also for all subsequent * asynchronous operations. * * If you think of chain of asynchronous operations as a thread of execution (bit of a stretch) * then [Zone#current] will act as a thread local variable. * * * * ## Asynchronous operation scheduling * * In addition to wrapping the callbacks to restore the zone, all operations which cause a * scheduling of work for later are routed through the current zone which is allowed to intercept * them by adding work before or after the wrapCallback as well as using different means of * achieving the request. (Useful for unit testing, or tracking of requests). In some instances * such as `setTimeout` the wrapping of the wrapCallback and scheduling is done in the same * wrapCallback, but there are other examples such as `Promises` where the `then` wrapCallback is * wrapped, but the execution of `then` is triggered by `Promise` scheduling `resolve` work. * * Fundamentally there are three kinds of tasks which can be scheduled: * * 1. [MicroTask] used for doing work right after the current task. This is non-cancelable which is * guaranteed to run exactly once and immediately. * 2. [MacroTask] used for doing work later. Such as `setTimeout`. This is typically cancelable * which is guaranteed to execute at least once after some well understood delay. * 3. [EventTask] used for listening on some future event. This may execute zero or more times, with * an unknown delay. * * Each asynchronous API is modeled and routed through one of these APIs. * * * ### [MicroTask] * * [MicroTask]s represent work which will be done in current VM turn as soon as possible, before VM * yielding. * * * ### [TimerTask] * * [TimerTask]s represent work which will be done after some delay. (Sometimes the delay is * approximate such as on next available animation frame). Typically these methods include: * `setTimeout`, `setImmediate`, `setInterval`, `requestAnimationFrame`, and all browser specific * variants. * * * ### [EventTask] * * [EventTask]s represent a request to create a listener on an event. Unlike the other task * events they may never be executed, but typically execute more than once. There is no queue of * events, rather their callbacks are unpredictable both in order and time. * * * ## Global Error Handling * * * ## Composability * * Zones can be composed together through [Zone.fork()]. A child zone may create its own set of * rules. A child zone is expected to either: * * 1. Delegate the interception to a parent zone, and optionally add before and after wrapCallback * hooks. * 2. Process the request itself without delegation. * * Composability allows zones to keep their concerns clean. For example a top most zone may choose * to handle error handling, while child zones may choose to do user action tracking. * * * ## Root Zone * * At the start the browser will run in a special root zone, which is configured to behave exactly * like the platform, making any existing code which is not zone-aware behave as expected. All * zones are children of the root zone. * */ interface Zone { /** * * @returns {Zone} The parent Zone. */ parent: Zone; /** * @returns {string} The Zone name (useful for debugging) */ name: string; /** * Returns a value associated with the `key`. * * If the current zone does not have a key, the request is delegated to the parent zone. Use * [ZoneSpec.properties] to configure the set of properties associated with the current zone. * * @param key The key to retrieve. * @returns {any} The value for the key, or `undefined` if not found. */ get(key: string): any; /** * Returns a Zone which defines a `key`. * * Recursively search the parent Zone until a Zone which has a property `key` is found. * * @param key The key to use for identification of the returned zone. * @returns {Zone} The Zone which defines the `key`, `null` if not found. */ getZoneWith(key: string): Zone; /** * Used to create a child zone. * * @param zoneSpec A set of rules which the child zone should follow. * @returns {Zone} A new child zone. */ fork(zoneSpec: ZoneSpec): Zone; /** * Wraps a callback function in a new function which will properly restore the current zone upon * invocation. * * The wrapped function will properly forward `this` as well as `arguments` to the `callback`. * * Before the function is wrapped the zone can intercept the `callback` by declaring * [ZoneSpec.onIntercept]. * * @param callback the function which will be wrapped in the zone. * @param source A unique debug location of the API being wrapped. * @returns {function(): *} A function which will invoke the `callback` through [Zone.runGuarded]. */ wrap(callback: F, source: string): F; /** * Invokes a function in a given zone. * * The invocation of `callback` can be intercepted by declaring [ZoneSpec.onInvoke]. * * @param callback The function to invoke. * @param applyThis * @param applyArgs * @param source A unique debug location of the API being invoked. * @returns {any} Value from the `callback` function. */ run(callback: Function, applyThis?: any, applyArgs?: any[], source?: string): T; /** * Invokes a function in a given zone and catches any exceptions. * * Any exceptions thrown will be forwarded to [Zone.HandleError]. * * The invocation of `callback` can be intercepted by declaring [ZoneSpec.onInvoke]. The * handling of exceptions can be intercepted by declaring [ZoneSpec.handleError]. * * @param callback The function to invoke. * @param applyThis * @param applyArgs * @param source A unique debug location of the API being invoked. * @returns {any} Value from the `callback` function. */ runGuarded(callback: Function, applyThis?: any, applyArgs?: any[], source?: string): T; /** * Execute the Task by restoring the [Zone.currentTask] in the Task's zone. * * @param task to run * @param applyThis * @param applyArgs * @returns {*} */ runTask(task: Task, applyThis?: any, applyArgs?: any): any; /** * Schedule a MicroTask. * * @param source * @param callback * @param data * @param customSchedule */ scheduleMicroTask(source: string, callback: Function, data?: TaskData, customSchedule?: (task: Task) => void): MicroTask; /** * Schedule a MacroTask. * * @param source * @param callback * @param data * @param customSchedule * @param customCancel */ scheduleMacroTask(source: string, callback: Function, data: TaskData, customSchedule: (task: Task) => void, customCancel: (task: Task) => void): MacroTask; /** * Schedule an EventTask. * * @param source * @param callback * @param data * @param customSchedule * @param customCancel */ scheduleEventTask(source: string, callback: Function, data: TaskData, customSchedule: (task: Task) => void, customCancel: (task: Task) => void): EventTask; /** * Schedule an existing Task. * * Useful for rescheduling a task which was already canceled. * * @param task */ scheduleTask(task: T): T; /** * Allows the zone to intercept canceling of scheduled Task. * * The interception is configured using [ZoneSpec.onCancelTask]. The default canceler invokes * the [Task.cancelFn]. * * @param task * @returns {any} */ cancelTask(task: Task): any; } interface ZoneType { /** * @returns {Zone} Returns the current [Zone]. The only way to change * the current zone is by invoking a run() method, which will update the current zone for the * duration of the run method callback. */ current: Zone; /** * @returns {Task} The task associated with the current execution. */ currentTask: Task; /** * Verify that Zone has been correctly patched. Specifically that Promise is zone aware. */ assertZonePatched(): void; /** * Return the root zone. */ root: Zone; } interface UncaughtPromiseError extends Error { zone: Zone; task: Task; promise: Promise; rejection: any; } /** * Provides a way to configure the interception of zone events. * * Only the `name` property is required (all other are optional). */ interface ZoneSpec { /** * The name of the zone. Useful when debugging Zones. */ name: string; /** * A set of properties to be associated with Zone. Use [Zone.get] to retrieve them. */ properties?: { [key: string]: any; }; /** * Allows the interception of zone forking. * * When the zone is being forked, the request is forwarded to this method for interception. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param zoneSpec The argument passed into the `fork` method. */ onFork?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, zoneSpec: ZoneSpec) => Zone; /** * Allows interception of the wrapping of the callback. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param delegate The argument passed into the `wrap` method. * @param source The argument passed into the `wrap` method. */ onIntercept?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, delegate: Function, source: string) => Function; /** * Allows interception of the callback invocation. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param delegate The argument passed into the `run` method. * @param applyThis The argument passed into the `run` method. * @param applyArgs The argument passed into the `run` method. * @param source The argument passed into the `run` method. */ onInvoke?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, delegate: Function, applyThis: any, applyArgs: any[], source: string) => any; /** * Allows interception of the error handling. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param error The argument passed into the `handleError` method. */ onHandleError?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, error: any) => boolean; /** * Allows interception of task scheduling. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param task The argument passed into the `scheduleTask` method. */ onScheduleTask?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, task: Task) => Task; onInvokeTask?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, task: Task, applyThis: any, applyArgs: any) => any; /** * Allows interception of task cancellation. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param task The argument passed into the `cancelTask` method. */ onCancelTask?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, task: Task) => any; /** * Notifies of changes to the task queue empty status. * * @param parentZoneDelegate Delegate which performs the parent [ZoneSpec] operation. * @param currentZone The current [Zone] where the current interceptor has been declared. * @param targetZone The [Zone] which originally received the request. * @param hasTaskState */ onHasTask?: (parentZoneDelegate: ZoneDelegate, currentZone: Zone, targetZone: Zone, hasTaskState: HasTaskState) => void; } /** * A delegate when intercepting zone operations. * * A ZoneDelegate is needed because a child zone can't simply invoke a method on a parent zone. For * example a child zone wrap can't just call parent zone wrap. Doing so would create a callback * which is bound to the parent zone. What we are interested in is intercepting the callback before * it is bound to any zone. Furthermore, we also need to pass the targetZone (zone which received * the original request) to the delegate. * * The ZoneDelegate methods mirror those of Zone with an addition of extra targetZone argument in * the method signature. (The original Zone which received the request.) Some methods are renamed * to prevent confusion, because they have slightly different semantics and arguments. * * - `wrap` => `intercept`: The `wrap` method delegates to `intercept`. The `wrap` method returns * a callback which will run in a given zone, where as intercept allows wrapping the callback * so that additional code can be run before and after, but does not associate the callback * with the zone. * - `run` => `invoke`: The `run` method delegates to `invoke` to perform the actual execution of * the callback. The `run` method switches to new zone; saves and restores the `Zone.current`; * and optionally performs error handling. The invoke is not responsible for error handling, * or zone management. * * Not every method is usually overwritten in the child zone, for this reason the ZoneDelegate * stores the closest zone which overwrites this behavior along with the closest ZoneSpec. * * NOTE: We have tried to make this API analogous to Event bubbling with target and current * properties. * * Note: The ZoneDelegate treats ZoneSpec as class. This allows the ZoneSpec to use its `this` to * store internal state. */ interface ZoneDelegate { zone: Zone; fork(targetZone: Zone, zoneSpec: ZoneSpec): Zone; intercept(targetZone: Zone, callback: Function, source: string): Function; invoke(targetZone: Zone, callback: Function, applyThis: any, applyArgs: any[], source: string): any; handleError(targetZone: Zone, error: any): boolean; scheduleTask(targetZone: Zone, task: Task): Task; invokeTask(targetZone: Zone, task: Task, applyThis: any, applyArgs: any): any; cancelTask(targetZone: Zone, task: Task): any; hasTask(targetZone: Zone, isEmpty: HasTaskState): void; } declare type HasTaskState = { microTask: boolean; macroTask: boolean; eventTask: boolean; change: TaskType; }; /** * Task type: `microTask`, `macroTask`, `eventTask`. */ declare type TaskType = 'microTask' | 'macroTask' | 'eventTask'; /** * Task type: `notScheduled`, `scheduling`, `scheduled`, `running`, `canceling`, 'unknown'. */ declare type TaskState = 'notScheduled' | 'scheduling' | 'scheduled' | 'running' | 'canceling' | 'unknown'; /** */ interface TaskData { /** * A periodic [MacroTask] is such which get automatically rescheduled after it is executed. */ isPeriodic?: boolean; /** * Delay in milliseconds when the Task will run. */ delay?: number; /** * identifier returned by the native setTimeout. */ handleId?: number; } /** * Represents work which is executed with a clean stack. * * Tasks are used in Zones to mark work which is performed on clean stack frame. There are three * kinds of task. [MicroTask], [MacroTask], and [EventTask]. * * A JS VM can be modeled as a [MicroTask] queue, [MacroTask] queue, and [EventTask] set. * * - [MicroTask] queue represents a set of tasks which are executing right after the current stack * frame becomes clean and before a VM yield. All [MicroTask]s execute in order of insertion * before VM yield and the next [MacroTask] is executed. * - [MacroTask] queue represents a set of tasks which are executed one at a time after each VM * yield. The queue is ordered by time, and insertions can happen in any location. * - [EventTask] is a set of tasks which can at any time be inserted to the end of the [MacroTask] * queue. This happens when the event fires. * */ interface Task { /** * Task type: `microTask`, `macroTask`, `eventTask`. */ type: TaskType; /** * Task state: `notScheduled`, `scheduling`, `scheduled`, `running`, `canceling`, `unknown`. */ state: TaskState; /** * Debug string representing the API which requested the scheduling of the task. */ source: string; /** * The Function to be used by the VM upon entering the [Task]. This function will delegate to * [Zone.runTask] and delegate to `callback`. */ invoke: Function; /** * Function which needs to be executed by the Task after the [Zone.currentTask] has been set to * the current task. */ callback: Function; /** * Task specific options associated with the current task. This is passed to the `scheduleFn`. */ data: TaskData; /** * Represents the default work which needs to be done to schedule the Task by the VM. * * A zone may choose to intercept this function and perform its own scheduling. */ scheduleFn: (task: Task) => void; /** * Represents the default work which needs to be done to un-schedule the Task from the VM. Not all * Tasks are cancelable, and therefore this method is optional. * * A zone may chose to intercept this function and perform its own un-scheduling. */ cancelFn: (task: Task) => void; /** * @type {Zone} The zone which will be used to invoke the `callback`. The Zone is captured * at the time of Task creation. */ readonly zone: Zone; /** * Number of times the task has been executed, or -1 if canceled. */ runCount: number; /** * Cancel the scheduling request. This method can be called from `ZoneSpec.onScheduleTask` to * cancel the current scheduling interception. Once canceled the task can be discarded or * rescheduled using `Zone.scheduleTask` on a different zone. */ cancelScheduleRequest(): void; } interface MicroTask extends Task { type: 'microTask'; } interface MacroTask extends Task { type: 'macroTask'; } interface EventTask extends Task { type: 'eventTask'; } declare const Zone: ZoneType;