ember-concurrency
Version:
Improved concurrency/async primitives for Ember.js
264 lines (246 loc) • 7.92 kB
JavaScript
import { BaseTaskInstance } from './external/task-instance/base.js';
import { TRACKED_INITIAL_INSTANCE_STATE } from './tracked-state.js';
/**
A `TaskInstance` represent a single execution of a
{@linkcode Task}. Every call to {@linkcode Task#perform} returns
a `TaskInstance`.
`TaskInstance`s are cancelable, either explicitly
via {@linkcode TaskInstance#cancel} or {@linkcode Task#cancelAll},
or automatically due to the host object being destroyed, or
because concurrency policy enforced by a
{@linkcode TaskProperty Task Modifier} canceled the task instance.
<style>
.ignore-this--this-is-here-to-hide-constructor,
#TaskInstance { display: none }
</style>
@class TaskInstance
*/
class TaskInstance extends BaseTaskInstance {
setState(props) {
let state = this._recomputeState(props);
Object.assign(this, {
...props,
isRunning: !props.isFinished,
isDropped: state === 'dropped',
state
});
}
_recomputeState(props) {
if (props.isDropped) {
return 'dropped';
} else if (props.isCanceled) {
if (props.hasStarted) {
return 'canceled';
} else {
return 'dropped';
}
} else if (props.isFinished) {
return 'finished';
} else if (props.hasStarted) {
return 'running';
} else {
return 'waiting';
}
}
onStarted() {
this.triggerEvent('started', this);
}
onSuccess() {
this.triggerEvent('succeeded', this);
}
onError(error) {
this.triggerEvent('errored', this, error);
}
onCancel(cancelReason) {
this.triggerEvent('canceled', this, cancelReason);
}
formatCancelReason(reason) {
return `TaskInstance '${this.getName()}' was canceled because ${reason}. For more information, see: http://ember-concurrency.com/docs/task-cancelation-help`;
}
getName() {
if (!this.name) {
this.name = this.task && this.task.name || '<unknown>';
}
return this.name;
}
selfCancelLoopWarning(parent) {
let parentName = `\`${parent.getName()}\``;
let childName = `\`${this.getName()}\``;
// eslint-disable-next-line no-console
console.warn(`ember-concurrency detected a potentially hazardous "self-cancel loop" between parent task ${parentName} and child task ${childName}. If you want child task ${childName} to be canceled when parent task ${parentName} is canceled, please change \`.perform()\` to \`.linked().perform()\`. If you want child task ${childName} to keep running after parent task ${parentName} is canceled, change it to \`.unlinked().perform()\``);
}
triggerEvent(...allArgs) {
if (!this.hasEnabledEvents) {
return;
}
let taskInstance = this;
let task = taskInstance.task;
let host = task.context;
let eventNamespace = task && task.name;
if (host && host.trigger && eventNamespace) {
let [eventType, ...args] = allArgs;
host.trigger(`${eventNamespace}:${eventType}`, ...args);
}
}
/**
* Describes the state that the task instance is in. Can be used for debugging,
* or potentially driving some UI state. Possible values are:
*
* - `"dropped"`: task instance was canceled before it started
* - `"canceled"`: task instance was canceled before it could finish
* - `"finished"`: task instance ran to completion (even if an exception was thrown)
* - `"running"`: task instance is currently running (returns true even if
* is paused on a yielded promise)
* - `"waiting"`: task instance hasn't begun running yet (usually
* because the task is using the {@linkcode TaskProperty#enqueue enqueue}
* task modifier)
*
* The animated timeline examples on the [Task Concurrency](/docs/task-concurrency)
* docs page make use of this property.
*
* @name state
* @memberof TaskInstance
* @instance
* @readOnly
*/
/**
* True if the TaskInstance was canceled before it could
* ever start running. For example, calling
* {@linkcode Task#perform .perform()} twice on a
* task with the {@linkcode TaskProperty#drop drop} modifier applied
* will result in the second task instance being dropped.
*
* @name isDropped
* @memberof TaskInstance
* @instance
* @readOnly
*/
/**
* True if the task is still running.
*
* @name isRunning
* @memberof TaskInstance
* @instance
* @readOnly
*/
/**
* Event emitted when a new {@linkcode TaskInstance} starts executing.
*
* `on` from `@ember/object/evented` may be used to create a binding on the host object to the event.
*
* ```js
* export default Component.extend({
* doSomething: task(function * () {
* // ... does something
* }),
*
* onDoSomethingStarted: on('doSomething:started', function (taskInstance) {
* // ...
* })
* });
* ```
*
* @event TaskInstance#TASK_NAME:started
* @param {TaskInstance} taskInstance - Task instance that was started
*/
/**
* Event emitted when a {@linkcode TaskInstance} succeeds.
*
* `on` from `@ember/object/evented` may be used to create a binding on the host object to the event.
*
* ```js
* export default Component.extend({
* doSomething: task(function * () {
* // ... does something
* }),
*
* onDoSomethingSucceeded: on('doSomething:succeeded', function (taskInstance) {
* // ...
* })
* });
* ```
*
* @event TaskInstance#TASK_NAME:succeeded
* @param {TaskInstance} taskInstance - Task instance that was succeeded
*/
/**
* Event emitted when a {@linkcode TaskInstance} throws an an error that is
* not handled within the task itself.
*
* `on` from `@ember/object/evented` may be used to create a binding on the host object to the event.
*
* ```js
* export default Component.extend({
* doSomething: task(function * () {
* // ... does something
* }),
*
* onDoSomethingErrored: on('doSomething:errored', function (taskInstance, error) {
* // ...
* })
* });
* ```
*
* @event TaskInstance#TASK_NAME:errored
* @param {TaskInstance} taskInstance - Task instance that was started
* @param {Error} error - Error that was thrown by the task instance
*/
/**
* Event emitted when a {@linkcode TaskInstance} is canceled.
*
* `on` from `@ember/object/evented` may be used to create a binding on the host object to the event.
*
* ```js
* export default Component.extend({
* doSomething: task(function * () {
* // ... does something
* }),
*
* onDoSomethingCanceled: on('doSomething:canceled', function (taskInstance, cancelationReason) {
* // ...
* })
* });
* ```
*
* @event TaskInstance#TASK_NAME:canceled
* @param {TaskInstance} taskInstance - Task instance that was started
* @param {string} cancelationReason - Cancelation reason that was was provided to {@linkcode TaskInstance#cancel}
*/
/**
* Cancels the task instance. Has no effect if the task instance has
* already been canceled or has already finished running.
*
* @method cancel
* @memberof TaskInstance
* @instance
* @async
*/
/**
* Returns a promise that resolves with the value returned
* from the task's (generator) function, or rejects with
* either the exception thrown from the task function, or
* an error with a `.name` property with value `"TaskCancelation"`.
*
* @method then
* @memberof TaskInstance
* @instance
* @return {Promise}
*/
/**
* @method catch
* @memberof TaskInstance
* @instance
* @return {Promise}
*/
/**
* @method finally
* @memberof TaskInstance
* @instance
* @return {Promise}
*/
}
if (TRACKED_INITIAL_INSTANCE_STATE) {
Object.defineProperties(TaskInstance.prototype, TRACKED_INITIAL_INSTANCE_STATE);
}
export { TaskInstance };
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