LostJS its a tiny library that adds some usefull methods to the native Js classes, it does not overwrite any of the standard methods.

npm install lostjs

require('lostjs');

import 'lostjs';

require('lostjs/common');

import 'lostjs/common';

In general, the method's name are very clear but, just in case, i wrote docs for u.

Converts an array to a circular object reference, usefull for carousels.

• ✅ The first object.
• ❌ If the array is empty: null.

import 'lostjs';

const circle = [1,2,3].circle();

/*
interface ICircleElement<T> {
    isLast: boolean, // true if the current object is the last.
    isFirst: boolean, // true if the current object is the first.
    index: number, // The current index in the array
    prev: ICircleElement<T>, // The previous element
    next: ICircleElement<T>, // The next element
    value: T // The value
}
*/

/* All objects has the same structure */
console.log(circle.value); // 1
console.log(circle.index); // 0

console.log(circle.next.value); // 2
console.log(circle.next.index); // 1

console.log(circle.prev.value); // 3
console.log(circle.prev.index); // 2

Get a value by an index, like Array.at but it's circular.

• ✅ if the array isn't empty: the value at the index.
• ❌ If the array is empty: undefined.

Get a value by an index, like Array.at but it's circular.

• ✅ if the array isn't empty: the value at the index.
• ❌ If the array is empty: undefined.

Rotate the array.

• 🔹 steps: number - The amount of steps to rotate, to right if positive, left if negative.
• 🔹 selector: (item, index, array) => boolean - A function that works as selector, should return true if the item might be rotated.

• ✅ A new array with rotated elements.
• ❌ An empty array if steps is zero or the referenced array is empty.

Fills an array with values.

• 🔹 filler: (index, array) => {continue: boolean, push?: boolean, value: any} - The function that returns the fill data.

The filler function should return an object with the action to realize in the fill's instance. If the continue member is true, the filling will continue. If push is true or undefined, the value will be pushed in the array, ignored otherwise. value will be the value with which the array will be filled, can be changed in the time.

• ✅ A new filled array.
• ❌ An empty array.

[].fillWith((index) => ({continue: index < 9, push: index !== 5, value: index*2}));
/*
[0,  2,  4,  6, 8, 12, 14, 16, 18]
*/

Splits an array.

• 🔹 steps: number - The amount of item to each array element.
• 🔹 byDivide: boolean = false - Use the divide metodology.

• ✅ A new array of arrays with the elements of the main array.

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10].split(2);
/*
[[1, 2], [3, 4], [5, 6], [7, 8], [9, 10]]
*/

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10].split(2, true);
/*
[[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
*/

Verify if the array is empty.

• ✅ if the array is empty: true.
• ❌ If the array isn't empty: false.

Get the index of the last element, equivalent to Array.length - 1.

• ✅ if the array isn't empty: Array.length - 1.
• ❌ If the array is empty: 0.

Get a random element from the array.

• ✅ if the array isn't empty: Array.length - 1.
• ❌ If the array is empty: undefined.

Verify if a number has decimals.

• ✅ if the number has decimals: true.
• ❌ If the number hasn't decimals: false.

Calls a function n times.

• 🔹 cb: (...args: any) => void - The callback that will be executed n times.
• 🔹 ...args: any - The arguments that will be passed to the callback.

If you pass '$' to the arguments, the counter will be passed to the callback.

(5).times(console.log, 'Hola Mundo');
/*
Hola Mundo
Hola Mundo
Hola Mundo
Hola Mundo
Hola Mundo
*/

(5).times(console.log, 'Hola Mundo', '$');
/*
Hola Mundo 0
Hola Mundo 1
Hola Mundo 2
Hola Mundo 3
Hola Mundo 4
*/

let i = 0;

(5).times(() => i++);
/*
i = 5;
*/

Verify if a number is between the range.

• ✅ if the number is between the range: true.
• ❌ If the number is not between the range: false.

Closes the number between a range.

• 🔹 min: number - The minimal value to get.
• 🔹 max: number - The maximal value to get.

• ✅ A number between the min and max.

Get a random number between a range.

• 🔹 param: {min?: number = 0, max?: number = Number.MAX_SAFE_INTEGER} - An object that defines the min and max range.

• ✅ A number between the min and max.