ember-concurrency-decorators

This Ember addon lets you use the decorator syntax for declaring/configuring ember-concurrency tasks.

Installation

You'll need at least ember-cli@2.13+ and ember-cli-babel@6+. Then install as any other addon:

ember install ember-concurrency-decorators

If you are not using TypeScript, in order for ember-cli-babel to understand the @decorator syntax, you at least also need to install @ember-decorators/babel-transforms. Instead of that you can also install the ember-decorators meta package:

ember install ember-decorators
# or
ember install @ember-decorators/babel-transforms

Usage

Available decorators

@task: turns a generator method into a task
- @restartableTask
- @dropTask
- @keepLatestTask
- @enqueueTask
@taskGroup: creates a task group from a property
- @restartableTaskGroup
- @dropTaskGroup
- @keepLatestTaskGroup
- @enqueueTaskGroup
@lastValue: alias a property to the result of a task with an optional default value

`@task`

import Component from '@ember/component';
import { task } from 'ember-concurrency-decorators';

export default class ExampleComponent extends Component {
  @task
  doStuff = function*() {
    // ...
  };

  // and then elsewhere
  executeTheTask() {
    // `doStuff` is still a `Task` object that can be `.perform()`ed
    this.doStuff.perform();
    console.log(this.doStuff.isRunning);
  }
}

You can also pass further options to the task decorator:

@task({
  maxConcurrency: 3,
  restartable: true
})
doStuff = function*() {
  // ...
}

For your convenience, there are extra decorators for all concurrency modifiers:

Shorthand	Equivalent
`@restartableTask`	`@task({ restartable: true })`
`@dropTask`	`@task({ drop: true })`
`@keepLatestTask`	`@task({ keepLatest: true })`
`@enqueueTask`	`@task({ enqueue: true })`

You can still pass further options to these decorators, like:

@restartableTask({ maxConcurrency: 3 })
doStuff = function*() {
  // ...
}

`@taskGroup`

import Component from '@ember/component';
import { task, taskGroup } from 'ember-concurrency-decorators';

export default class ExampleComponent extends Component {
  @taskGroup
  someTaskGroup;

  @task({ group: 'someTaskGroup' })
  doStuff = function*() {
    // ...
  };

  @task({ group: 'someTaskGroup' })
  doOtherStuff = function*() {
    // ...
  };

  // and then elsewhere
  executeTheTask() {
    // `doStuff` is still a `Task `object that can be `.perform()`ed
    this.doStuff.perform();

    // `someTaskGroup` is still a `TaskGroup` object
    console.log(this.someTaskGroup.isRunning);
  }
}

You can also pass further options to the task group decorator:

@taskGroup({
  maxConcurrency: 3,
  drop: true
}) someTaskGroup;

As for @task, there are extra decorators for all concurrency modifiers:

Shorthand	Equivalent
`@restartableTaskGroup`	`@taskGroup({ restartable: true })`
`@dropTaskGroup`	`@taskGroup({ drop: true })`
`@keepLatestTaskGroup`	`@taskGroup({ keepLatest: true })`
`@enqueueTaskGroup`	`@taskGroup({ enqueue: true })`

You can still pass further options to these decorators, like:

@dropTaskGroup({ maxConcurrency: 3 }) someTaskGroup;

`@lastValue`

This decorator allows you to alias a property to the result of a task. You can also provide a default value to use before the task has completed.

import Component from '@ember/component';
import { task } from 'ember-concurrency-decorators';
import { lastValue } from 'ember-concurrency-decorators';

export default class ExampleComponent extends Component {
  @task
  someTask = function*() {
    // ...
  };

  @lastValue('someTask')
  someTaskValue;

  @lastValue('someTask')
  someTaskValueWithDefault = 'A default value';
}

Syntax

TypeScript

Assuming you are using ember-cli-typescript, you can just use native ES6 class syntax with decorators on generator methods.

import Component from '@ember/component';
import { restartableTask } from 'ember-concurrency-decorators';

export default class ExampleComponent extends Component {
  @restartableTask
  *doStuff() {
    // ...
  }
});

// elsewhere:
this.doStuff.perform();

If you use @babel/plugin-transform-typescript with @babel/plugin-proposal-decorators in loose mode (as you currently must), you can't use the above syntax. Instead read on below:

JavaScript

If you are using plain old JavaScript, use the decorators like this:

import Component from '@ember/component';
import { restartableTask } from 'ember-concurrency-decorators';

export default class ExampleComponent extends Component {
  @restartableTask
  doStuff = function*() {
    // ...
  }
});

// elsewhere:
this.doStuff.perform();

You need to use this assignment / initializer syntax instead of "proper" generator methods, because of a bug in the loose mode of @babel/plugin-proposal-decorators, which ember-decorators depends on. When ember-decorators adds support for stage 2 decorators, you will be able to use the generator method syntax as well. 🎉

License

This project is licensed under the MIT License.

jacojoubert/ember-concurrency-decorators