Module to schedule a function to be invoked after a variable time, chosen on the fly.

✨ Demo

Install

npm i -s variable-interval

Usage

// We are going to implement exponential backoff.
const {
  setVariableInterval,
  clearVariableInterval,
} = require("variable-interval");

// invocationCount is count of how many times
// the function has been called, starting from 1.
async function makeRequest(invocationCount) {
  // Take the action
  // await makeApiRequest(state.url);
}

function getWaitTime(invocationCount) {
  if (invocationCount === 10) {
    // Negative value stops the interval
    return -1;
  }
  // The return value is the next wait time
  return Math.pow(2, invocationCount);
}

const intervalId = setVariableInterval(makeRequest, getWaitTime);

// You can also clear the interval manually
// Clearing the interval after 20 secs.
setTimeout(() => clearVariableInterval(intervalId), 20 * 1000);

API

setVariableInterval(exec, next, ...params)

This function schedule exec to be executed after time returned from the next function.

• exec: the function to be executed after each interval expires.

• next: the function that returns the time after which next call to exec will be made. A negative return value terminates the interval.

• params: any extra parameters passed would be passed to both exec and next.

Returns the intervalId(string) that can be used with clearVariableInterval

the first parameter for both exec and next is the count of how many times they have been called

setVariableInterval(intervalId)

This function will stop the scheduling of exec right away.

• intervalId: the intervalId obtained from setVariableInterval

Maintainer

👤 Akarshit Wal

• Twitter: @akarshitwal
• Github: @akarshit
• LinkedIn: @akarshit-wal

Thanks to @akshendra for his inputs.

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