What's the Most Efficient Way to Create a JavaScript Array from 1 to N?

How to Efficiently Generate an Array Containing 1...N in JavaScript

Original code:

var foo = [];

for (var i = 1; i <= N; i++) {
   foo.push(i);
}

While this approach is straightforward, it involves an explicit loop, which may not be the most efficient option. Here are some alternatives for creating an array containing 1 through N without the loop:

ES6 Array.from() and keys() Methods

In ES6 and above, you can utilize the Array.from() method along with the keys() method.

Array.from(Array(10).keys())
// => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Shorter Version Using Spread Operator

You can make the code even more concise using the spread operator.

[...Array(10).keys()]
// => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Starting from 1 with map Function

To start the array from 1 instead of 0, you can use the map function with an object having a length property.

Array.from({length: 10}, (_, i) => i + 1)
// => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

These alternatives provide more efficient ways to create an array containing a range of numbers without the need for explicit loops.

The above is the detailed content of What's the Most Efficient Way to Create a JavaScript Array from 1 to N?. For more information, please follow other related articles on the PHP Chinese website!