loop

A higher-order loop function for JavaScript that behaves like a flexible for or while loop. This package allows you to define your own loop logic with custom start values, test conditions, update rules, and body functions.

Table of Contents

• loop
  • Table of Contents
  • Installation
  • Usage
  • API
    • loop(value, test, update, body)
      • Parameters
      • Return Value
  • Examples
    • Basic Countdown
    • Count Up
    • Custom Step
  • Advanced Usage

Installation

Install via NPM:

npm install loop

Or using Yarn:

yarn add loop

Usage

Import the loop function:

const loop = require('loop');

// Or with ES Modules
import loop from 'loop';

API

loop(value, test, update, body)

A higher-order function that simulates a customizable loop.

Parameters

• value
  Type: any
  Description: The initial value to start the loop with.

• test
  Type: (currentValue) => boolean
  Description: A function that is called before each iteration. The loop continues only if it returns true.

• update
  Type: (currentValue) => any
  Description: A function that generates the next value for the loop after each iteration.

• body
  Type: (currentValue) => void
  Description: A function called on each iteration, receiving the current loop value. This is where you put the code to execute.

Return Value

The function does not return a value. It executes the body function for each iteration until the test function returns false.

Examples

Basic Countdown

const loop = require('loop');

loop(
    3,                 // starting value
    (i) => i > 0,      // test function
    (i) => --i,        // update function
    (i) => console.log(i)  // body function
);

// Output:
// 3
// 2
// 1

Count Up

loop(
    0,
    (i) => i < 5,
    (i) => i + 1,
    (i) => console.log(`Current value: ${i}`)
);

// Output:
// Current value: 0
// Current value: 1
// Current value: 2
// Current value: 3
// Current value: 4

Custom Step

loop(
    10,
    (i) => i > 0,
    (i) => i - 2,
    (i) => console.log(i)
);

// Output:
// 10
// 8
// 6
// 4
// 2

Advanced Usage

• You can pass any type as value (number, object, array, etc.)
• test and update can contain complex logic, enabling dynamic loops.
• This function can replace traditional for or while loops in functional programming styles.