Semaphore

Semaphore

A simple Semaphore implementation which provides a limited queue for ensuring proper concurrency.

Constructor

new Semaphore(maxopt)

Example
// Some async function that takes time to execute
function fn(x) {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log(x);
      resolve(x);
    }, 1000));
  }
};

// Create a Semaphore and add many concurrent tasks
const semaphore = new Semaphore(1);
for ( let i of Array.fromRange(100) ) {
  semaphore.add(fn, i);
}
Parameters:
Name Type Attributes Default Description
max number <optional>
1

The maximum number of tasks which are allowed concurrently.

Members

active :number

The number of actively executing tasks

Type:
  • number

max :number

The maximum number of tasks which can be simultaneously attempted.

Type:
  • number

remaining :number

The number of pending tasks remaining in the queue

Type:
  • number

Methods

add(fn, …argsopt)

Add a new tasks to the managed queue

Parameters:
Name Type Attributes Description
fn function

A callable function

args * <optional>
<repeatable>

Function arguments

clear()

Abandon any tasks which have not yet concluded