# unicorn/no-new-array

> Disallow `new Array()` with a single argument

`new Array(value)` does two different things. If `value` is a number, you get an array of that length with nothing in it. If it's anything else, you get an array with `value` as its only item. You can't tell which one is meant without knowing the type of `value`.

The rule suggests both readings: `Array.from({length: value})` and `[value]`. It can't know which one you meant, so `--fix` leaves the code alone. `--fix-dangerously` applies the first one.

{/* Generated by src/codegen/lint-rule-docs.ts. Do not edit this section. */}

## Configure

Off by default. To turn it on:

```toml bunfig.toml
[lint.rules]
"unicorn/no-new-array" = "error" # or "warn"
```

{/* End of the generated section. */}

## Examples

Reported:

{/* bad {"count": 2} */}
```js
const slots = new Array(10);
const list = new Array(input);
```

Not reported:

{/* good */}
```js
const slots = Array.from({ length: 10 });
const list = [input];
```

Only the form with exactly one argument is ambiguous:

{/* good */}
```js
const empty = new Array();
const pair = new Array(1, 2);
```