Comprehensive Guide to Fill Range and Its API for JavaScript Developers

Welcome to our comprehensive guide on fill-range, an incredibly useful utility for generating ranges in JavaScript. This library is highly versatile and helps developers create arrays of numbers or strings in a specific range with various step increments. In this guide, we will introduce you to the fill-range library, showcase several API examples, and provide an app example that utilizes the introduced APIs.

Getting Started with Fill Range

The fill-range library provides a flexible way to generate ranges. Let’s start with a basic installation:

  npm install fill-range

Basic Usage

Using fill-range is straightforward. Here’s a simple example:

  const fill = require('fill-range');

  // Generate a range of numbers from 1 to 5
  const range1 = fill(1, 5);
  console.log(range1); // Output: [ 1, 2, 3, 4, 5 ]

Specifying Steps

You can specify steps between numbers in the range. Here’s how:

  // Generate numbers from 1 to 10 with a step of 2
  const range2 = fill(1, 10, { step: 2 });
  console.log(range2); // Output: [ 1, 3, 5, 7, 9 ]

Handling Letters

Fill-range also supports creating ranges with letters:

  // Generate letters from 'a' to 'e'
  const range3 = fill('a', 'e');
  console.log(range3); // Output: [ 'a', 'b', 'c', 'd', 'e' ]

Reverse Ranges

Creating ranges in reverse order is equally simple:

  // Generate a range from 5 to 1
  const range4 = fill(5, 1);
  console.log(range4); // Output: [ 5, 4, 3, 2, 1 ]

Zero-Padding

You can create zero-padded ranges which are useful for formatting:

  // Generate zero-padded numbers from 01 to 05
  const range5 = fill('01', '05');
  console.log(range5); // Output: [ '01', '02', '03', '04', '05' ]

Filling Custom Arrays

Fill an existing array using fill-range:

  const array = Array(5).fill(null);
  fill(array, 0, 4);
  console.log(array); // Output: [ 0, 1, 2, 3, 4 ]

App Example

Let’s create a small app that generates a user-selectable range of numbers:

  const express = require('express');
  const fill = require('fill-range');

  const app = express();
  const port = 3000;

  app.get('/range', (req, res) => {
    const start = parseInt(req.query.start);
    const end = parseInt(req.query.end);
    const step = parseInt(req.query.step) || 1;

    const range = fill(start, end, { step });
    res.json(range);
  });

  app.listen(port, () => {
    console.log(`Server is running on http://localhost:$${port}`);
  });

Now, you can make requests to http://localhost:3000/range?start=1&end=10&step=2 and get the generated range as the response.

Explore the versatile fill-range library today and enhance your JavaScript projects with dynamic range generation!

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