operationkit
Inspired by Operation and OperationQueue classes from Apple's Foundation framework for macOS, iOS, watchOS, and tvOS.
Universal package for the browser and node.js
Installation
with node:
npm install operationkit
with yarn:
yarn add operationkit
with cdn:
<script src="https://unpkg.com/operationkit/dist/operationkit.min.js"></script>
Classes
Use
const {
Operation,
OpreationQueue,
BlockOperation,
GroupOperation,
OperationEvent,
QueueEvent,
QueuePriority
} = require('operationkit');Operation
An abstract class that represents a single task.
const operation = new Operation();
const result = await operation.start();Extend the Operation class for complex tasks
class ValidateTokenOperation extends Operation {
/**
* Method to implement to run custom task
* @override
* @returns {Promise}
*/
run() {
[...]
}
}Example
class DownloadDataOperation extends Operation {
/**
* @override
*/
async run() {
try {
const response = await axios.get('<some_api>');
return response.data;
} catch (e) {
this.cancel();
}
}
}
const apiOperation = new DownloadDataOperation();
The run function must always return a promise.
run() {
return new Promise((resolve, reject) => {
[...]
})
}or simply use async keyword when overriding the function.
async run() {
[...]
}Add dependencies
The operation will execute only when all dependencies are resolved.
operation1.dependencies = [operation2];
operation1.start()Console:
// operation2 started
// operation2 done
// operation1 started
// operation1 done
Create a collection of complex operations that represents your application
const validateToken = new ValidateTokenOperation();
const getUsersApi = new GetUsersApi();
getUsersApi.dependencies = [validateToken];
getUsersApi.completionCallback = operation => {
// operation.result;
};
getUsersApi.start()
.then(result => { ... })
.catch(e => { ... });Or set the dependency directly in the subclass:
class GetUsersApi extends Operation {
constructor() {
this.dependencies = [new ValidateTokenOperation()];
}
}Operation Events
- OperationEvent.START Operation has started to run the task
- OperationEvent.READY Operation is ready to be executed
- OperationEvent.DONE Operation is finished running the task
- OperationEvent.CANCEL Operation was cancelled
- OperationEvent.ERROR An error occured while running the task
apiOperation.on(OperationEvent.START, (operation) => {
console.log(operation);
})OperationQueue
A queue orchestrates the execution of operations. An operation queue executes its queued Operation objects based on their priority and readiness*.
const operationQueue = new OperationQueue();
const operation1 = new ApiOperation();
const operation2 = new ApiOperation();
operationQueue.addOperations([operation1, operation2]);Utilizing OperationQueue's maximum concurrent operations
operationQueue.maximumConcurentOperations = 2;Console:
// operation1 started
// operation2 started
// operation1 done
// operation2 done
Queue Priority
Specify the relative ordering of operations that are waiting to be started in an operation queue.
QueuePriority.veryHigh
QueuePriority.high
QueuePriority.normal
QueuePriority.low
QueuePriority.veryLowThese constants let you prioritize the order in which operations execute:
const getCacheData = new GetCacheDataOperation();
getCacheData.queuePriority = QueuePriority.high;
const downloaHighRestImage = new DownloaHighRestImageOperation();
getCacheData.queuePriority = QueuePriority.normal;
operationQueue.addOperations([getCacheData, downloaHighRestImage]);Console:
// getCacheData started
// getCacheData done
// downloaHighRestImage started
// downloaHighRestImage done
Inserting operations in a queue to control flow
const blockOperation6 = new BlockOperation(6, async () => {
const response = await axios.get('https://samples.openweathermap.org/data/2.5/weather?lat=35&lon=139&appid=b6907d289e10d714a6e88b30761fae22');
const data = response.data;
return data;
});
const operation = new DownloadDataOperation(1);
const operation2 = new DownloadDataOperation(2);
const operation3 = new DownloadDataOperation(3);
const operation4 = new TimeOutOperation(4, 2000);
const operation5 = new TimeOutOperation(5, 1000);
const operation7 = new TimeOutOperation(7, 8000);
const operation8 = new TimeOutOperation(8, 1500);
operation.dependencies = [operation2, operation7];
operation2.dependencies = [operation4, operation8];
operation3.dependencies = [operation, operation5, operation2];
operation4.dependencies = [operation5, blockOperation6];
operation5.dependencies = [blockOperation6];
operation8.dependencies = [operation7];
const operationQueue = new OperationQueue();
operationQueue.maximumConcurentOperations = 10;
operationQueue.completionCallback = () => {
console.log('queue done');
};
operationQueue.addOperations([operation3]);
OperationQueue Events
- OperationEvent.DONE OperationQueue has finished running all operations
- OperationEvent.PAUSED OperationQueue has paused
- OperationEvent.RESUMED OperationQueue has resumed
queue.on(OperationEvent.PAUSED, (operationQueue) => {
console.log(operationQueue);
})BlockOperation
A helper class that accepts a function which will be exexuted as the operation's task.
const operation = new BlockOperation(async () => {
return new Promise((resolve, reject) => {
setTimeout(() => {
resolve('my operation result');
}, 1000);
})
});
const result = await operation.start()
console.log(result) // 'my operation result'GroupOperation
Group multiple operations and return the result of each operation when they are all resolved.
const groupOperation = new GroupOperation();
groupOperation.addOperation(new GetUsersApi());
groupOperation.addOperation(new GetPostsApi());
const [users, posts] = await groupOperation.start();QueuePriorities are also considered when using GroupOperation.
Run tests
npm run testRun coverage
npm run test-coverageRun new build
npm run build
