✨ ✨ An extensible 1.5KB JavaScript utility for generating integers ⚡ 💪 🔥

About

A simple Javascript utility that can generate a range of integers, from simple ranges like even and odd numbers, to multiples of a given number, all with configurable spacing between the number sequencies.

You can also easily extend the utility to generate special custom sequencies for your unique needs. See the bundled leap-year plugin for sample extension plugin

Why

This utility can be used anyhow you deem fit, but the codebase and repository exists mostly for demonstration and educational purposes. The goal is to show how this could be built, and maybe walk through the procees of doing so (with a youtube playlist 😏) while highlighting some best practices. If you feel this should become an NPM package, let me know on Twitter

Usage

1. To get started, clone this repository to your local machine and go into the int-range directory

   git clone https://github.com/chalu/int-range.git
   cd int-range

2. Install all dependencies to complete the setup. Use NPM or Yarn depending on what you already have setup on your machine.

   npm install --save

   yarn install

3. View the examples by running any of the following commands and opening the displayed URL in a browser

   npm run demo

   yarn demo

Examples

See this demo from the docs folder for more usage samples

1. Generate 1 to 5

   ints({ from: 1, till: 5 });

2. Generate 0 to 15, in steps of 3

   ints({ from: 0, till: 15, stepsOf: 3 });
   // output: 0, 3, 6, 9, 12, 15

3. Generate integers between 25 and 1, in descending order, each integer spaced out by 5

   ints({ from: 25, till: 1, stepsOf: 5 });
   // output: 25, 20, 15, 10, 5

4. Generate a sequence of every other multiple of 5 between 1 and 50

   ints({
     from: 1,
     till: 35,
     sequence: multiples({ of: 5, stepsOf: 2 }),
     // output: 1, 10, 20, 30
   });

BYOS

Bring Your Own Sequence (BYOS), a.k.a extensibility!

Have need for a custom or domain specific integer sequence? You simply need to make a validator function!

1. Import the util's sequencer engine

   import { sequencer } from "../int-range.js";

2. Declare and export your custom range function. It will be called with an object parameter

   export const myCustomIntRange = (opts = {}) => {};

3. Define a validator function. It should return true when its value parameter is a bonafide integer in your custom sequence. This validator function should be set as the validator property of the object parameter passsed to your custom range function

   export const myCustomIntRange = (opts = {}) => {
     opts.validator = (value) => {
       // determine if value meets the requirement
       // for members of your custom range,
       // then return true, otherwise return false.
     };
   };

4. Call the sequencer function with your input parameter and return the outcome. Your complete integer sequence extension should look like:

   import { sequencer } from "../int-range.js";
   
   export const myCustomIntRange = (opts = {}) => {
       opts.validator = (value) => {
           if(/* value meets member requirements */) return true;
   
           return false;
       }
   
       return sequencer(opts);
   }

5. Finally, use myCustomIntRange to generate your desired sequence of integers

   import { ints } from "../int-range.js";
   import { myCustomIntRange } from "./path/to/my-custom-int-range.js";
   
   const numbers = ints({
     from: 5,
     till: 200,
     sequence: myCustomIntRange({ stepsOf: 2 }),
   });
   
   console.log(numbers);

Take a look at the leap year sample and see how super easy it is to extend int-range.js to sequence custom domain specific integer ranges.

LICENSE

MIT