How to work with an array

JavaScriptJunior~1 min read

You can create an array in JavaScript in several ways, and each one fits different cases.

1. With an array literal (the most common and simplest way)

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const fruits = ["apple", "banana", "cherry"];

The elements go inside square brackets [].
This is the fastest and most readable way.
You can store values of different types:

javascript
const mixed = [1, "text", true, { name: "Tim" }, [10, 20]];

javascript

const numbers = new Array(1, 2, 3);

But there is a nuance:

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const arr = new Array(5);
console.log(arr); // [ <5 empty items> ]

If you pass a single argument that is a number, it creates an empty array with length 5, not [5].

To create [5], you need to do this:

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const arr = [5];

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const empty = [];

You can add elements later:

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empty.push("apple");
empty.push("banana");
console.log(empty); // ["apple", "banana"]

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const letters = Array.from("hello");
console.log(letters); // ['h', 'e', 'l', 'l', 'o']

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const set = new Set([1, 2, 3]);
const arr = Array.from(set); // [1, 2, 3]

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function example() {
  const args = Array.from(arguments);
  console.log(args);
}
example(1, 2, 3); // [1, 2, 3]

Creates an array from any arguments, even a single number:

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const arr = Array.of(5); // [5]
const arr2 = Array.of(1, 2, 3); // [1, 2, 3]

Way	Example	Features
Literal	`[]` or `[1, 2]`	the simplest and safest
`new Array()`	`new Array(3)`	creates an array of length 3, if 1 argument
`Array.of()`	`Array.of(3)`	creates `[3]`, without confusion
`Array.from()`	`Array.from("abc")`	turns iterable objects into an array

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