@putout/plugin-new [![NPM version][NPMIMGURL]][NPMURL]

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[NPMURL]: https://npmjs.org/package/@putout/plugin-new "npm"

> The new operator lets developers create an instance of a user-defined object type or of one of the built-in object types that has a constructor function.
>
> (c) MDN

🐊Putout plugin adds ability to add missing and remove useless operator new.

Install

``
npm i @putout/plugin-new
`

Rule

`json
{
"rules": {
"new/remove-useless": "on",
"new/add-missing": "on"
}
}
`

remove-useless

Operator new has no sense for Boolean, String, Number, Object, RegExp, Math, Reflect, Error, TypeError:

> Thus the function call Error(…) is equivalent to the object creation expression new Error(…) with the same arguments.
>
> (c) https://262.ecma-international.org/12.0/#sec-error-constructor

And Symbol, BigInt cannot be used with new, as it is primitive.

$3

`js
new Error('Something went wrong');
new new Boolean()();
`

$3

`js
Error('Something went wrong');
Boolean();
`

add-missing

> The Set constructor lets you create Set objects that store unique values of any type, whether primitive values or object references.
>
> (c) MDN

Missing operator new should be added since built-in objects:

- Set;
- WeakSet;
- Map;
- WeakMap;
- Int8Array;
- Uint8Array;
- Uint8ClampedArray;
- Int16Array;
- Uint16Array;
- Int32Array;
- Uint32Array;
- Float32Array;
- Float64Array;
- BigInt64Array;
- BigUint64Array;

Produces TypeError when called without new:

`
Uncaught TypeError: Constructor Set requires 'new'
`

$3

`js
const map = Map();
`

$3

`js
const map = new Map();
`

Comparison

Linter | Rule | Fix
--------|-------|------------|
🐊 Putout | remove-useless-new| ✅
⏣ ESLint | no-new-wrappers | ❌
⠀| no-new-object | ❌
⠀| no-array-constructor | ❌
⠀| no-new-symbol | ❌
⠀| no-new-native-constructor` | ❌

License

MIT