range-pie v1.0.1

range-pie

A JavaScript library that brings Python's range functionality to JavaScript, enhanced with familiar array methods. This lightweight utility provides a seamless way to work with numeric sequences while maintaining JavaScript's functional programming paradigm.

Table of Contents

• Installation
• Basic Usage

• API Reference

  • Constructor Options
  • Properties
  • at()
  • toString()
  • toArray()
  • map()
  • filter()
  • reduce()
  • some()
  • every()
  • find()
  • findIndex()
  • findLastIndex()
  • forEach()
  • includes()
  • indexOf()
  • lastIndexOf()
  • reverse()

• Advanced Usage

  • Iteration
  • Proxy Access

• Examples

  • Methods chaining
  • Using as Array-like Object

Installation

npm install range-pie

Basic Usage

const { PyRange } = require('range-pie');

// Create a range from 0 to 5
const range = new PyRange(5);
console.log([...range]); // [0, 1, 2, 3, 4]

// Create a range with start and stop
const range2 = new PyRange(2, 8);
console.log([...range2]); // [2, 3, 4, 5, 6, 7]

// Create a range with step
const range3 = new PyRange(0, 10, 2);
console.log([...range3]); // [0, 2, 4, 6, 8]

API Reference

Constructor Options

new PyRange(stop)               // 0 to stop-1
new PyRange(start, stop)        // start to stop-1
new PyRange(start, stop, step)  // start to stop-1 with step

• PyRange(stop:number)

console.log(PyRange(10));
// PyRange { _start: 0, _stop: 10, _step: 1, _length: 10 }

console.log(PyRange(-5));
// PyRange { _start: 0, _stop: -5, _step: -1, _length: 5 }

• PyRange(start:number, stop:number)

console.log(PyRange(1, 10));
// PyRange { _start: 1, _stop: 10, _step: 1, _length: 9 }

console.log(PyRange(-10, 0));
// PyRange { _start: -10, _stop: 0, _step: 1, _length: 10 }

• PyRange(start:number, stop:number, step:number)

console.log(PyRange(2, 5, 2));
// PyRange { _start: 2, _stop: 5, _step: 2, _length: 2 }

console.log(PyRange(2, -10, -1));
// PyRange { _start: 2, _stop: -10, _step: -1, _length: 12 }

Properties

const range = new PyRange(1, 10, 2);
console.log(range.start);  // 1
console.log(range.stop);   // 10
console.log(range.step);   // 2
console.log(range.length); // 5

at()

The 'at' method accepts a number as argument to gets the value at the specified index in a range. Generate a RangeError if the index is out of range.

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.at(0));  // 1
console.log(range.at(2));  // 3
console.log(range.at(-1)); // RangeError

toString()

Transform a PyRange object to a string representation.

const range = new PyRange(1, 10, 2);
console.log(range.toString()); // "PyRange(1, 10, 2)"

toArray()

Transform a PyRange object to an JavaScript array

const range = new PyRange(1, 4);
console.log(range.toArray()); // [1, 2, 3]

map()

It works the same as Array.prototype.map

const range = new PyRange(1, 4);  // [1, 2, 3]
console.log(range.map(x => x * 2));  // [2, 4, 6]

filter()

It works the same as Array.prototype.filter

const range = new PyRange(1, 6);  // [1, 2, 3, 4, 5]
console.log(range.filter(x => x % 2 === 0));  // [2, 4]

reduce()

It works the same as Array.prototype.reduce

const range = new PyRange(1, 4);  // [1, 2, 3]
const sum = range.reduce((acc, curr) => acc + curr, 0);
console.log(sum);  // 6

some()

It works the same as Array.prototype.some

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.some(x => x > 3));  // true
console.log(range.some(x => x < 0));  // false

every()

It works the same as Array.prototype.every

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.every(x => x > 0));  // true
console.log(range.every(x => x > 2));  // false

find()

It works the same as Array.prototype.find

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.find(x => x > 2));  // 3
console.log(range.find(x => x > 5));  // undefined

findIndex()

It works the same as Array.prototype.findIndex

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.findIndex(x => x > 2));  // 2
console.log(range.findIndex(x => x > 5));  // -1

findLastIndex()

It works the same as Array.prototype.findLastIndex

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.findLastIndex(x => x > 2));  // 3
console.log(range.findLastIndex(x => x > 5));  // -1

forEach()

It works the same as Array.prototype.forEach

const range = new PyRange(1, 4);  // [1, 2, 3]
range.forEach(x => console.log(x));  
// 1
// 2
// 3

includes()

It works the same as Array.prototype.includes

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.includes(3));  // true
console.log(range.includes(5));  // false

indexOf()

It works the same as Array.prototype.indexOf

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log(range.indexOf(3));    // 2
console.log(range.indexOf(5));    // -1

lastIndexOf()

It works the same as Array.prototype.lastIndexOf

const range = new PyRange(1, 5, 1);  // [1, 2, 3, 4]
console.log(range.lastIndexOf(3));    // 2
console.log(range.lastIndexOf(5));    // -1

reverse()

It works the same as Array.prototype.reverse

const range = new PyRange(1, 5);  // [1, 2, 3, 4]
console.log([...range]);          // [1, 2, 3, 4]

const reversed = range.reverse(); // [4, 3, 2, 1]
console.log([...reversed]);      // [4, 3, 2, 1]

const rangeWithStep = new PyRange(1, 10, 2);  // [1, 3, 5, 7, 9]
const reversedStep = rangeWithStep.reverse(); // [9, 7, 5, 3, 1]
console.log([...reversedStep]);

Advanced Usage

Iteration

const range = new PyRange(3);

// For...of loop
for (const num of range) {
    console.log(num); // 0, 1, 2
}

// Spread operator
const array = [...range]; // [0, 1, 2]

Proxy Access

Proxy access allows access to the array elements using bracket notation, just like a regular array.

const range = new PyRange(5);
const proxy = range.asProxy();

console.log(proxy[0]); // 0
console.log(proxy[3]); // 3

Examples

Methods chaining

const range = new PyRange(1, 6);
const squares = range
    .filter(x => x % 2 === 0)
    .map(x => x * x);
console.log(squares); // [4, 16]

Using as Array-like Object

const range = new PyRange(5).asProxy();
const firstThree = [range[0], range[1], range[2]];
console.log(firstThree); // [0, 1, 2]