ts-waitgroup

A WaitGroup waits for a collection of async functions to finish.

This module simulates the working of the WaitGroup type of the sync package of the Go programming language.

The module implements a WaitGroup class, that waits for a collection of asynchronous function to finish.

The main function, that uses the WaitGroup initializes its counter or, calls the add() method to set the number of async functions to wait for. Then each of the async functions runs and calls done() when finished. The done() function must be called as many times the counter was set to. At the same time, wait() can be used to block until all async functions have finished. The done() calls may have a result: any parameter. In this case the parameter of the last done() call will be the return value of the wait() function.

If there is a problem, the fail() call will break the execution, so the wait() will return immediately with the optional result: any parameter that was given to the fail() call.

Usage

    // Start a wait-group with more than one items
    const wg = new WaitGroup(3);

    // Start async function-1
    setTimeout(() => {
        wg.done('OK');
    }, 10);

    // Start async function-2
    setTimeout(() => {
        wg.done('OK');
    }, 20);

    // Start async function-3
    setTimeout(() => {
        wg.done('OK');
    }, 30);

    // Wait for the completion of the async functions
    const result = await wg.wait();
    // result = 'OK'

See the unit tests for more examples.

See also the API docs.

Development

It uses the following tools:

• TypeScript
• ESLint
• Prettier
• Jest
• Taskfile

Build

To compile TypeScript code use the following command:

task build

This will create a "dist" folder in which all the compiled JavaScript files appear.

Run lint

This project uses ESLint with Prettier, Airbnb and recommended TypeScript configurations. In order to start lint locally, use this command:

task lint

Test with coverage

Test files can be found beside the corresponding source files. Every test file name must follow the "*.test.ts" pattern. To run these tests and generate coverage report, use this command:

task test

The generated coverage report can be found under the "coverage" folder.

Clean project

To remove the "build" and "coverage" folders you can run the clean command.

task clean

License

The code and documentation in this project are released under the MIT License