Spread syntax can be used when all elements from an object or array need to be included in a list of some kind.
(c) MDN
🐊Putout plugin adds ability to remove useless spread syntax.
npm i @putout/plugin-remove-useless-spread
{
"rules": {
"remove-useless-spread/array": "on",
"remove-useless-spread/object": "on",
"remove-useless-spread/nested": "on"
}
}
The thing is [...b]
can be used for:
- copying an array;
- converting different value type like
string
to anarray
.
So better to be more concrete and use slice
for copying and Array()
/Array.from()
for converting to decrease cognitive load.
Also sometimes there is no need on any of this operations, and we can drop spread
.
for (const a of [...b]) {}
const places = [...getPlaces()];
for (const a of b) {}
const places = getPlaces();
// Array constructor creates sparse array
[...Array(5)].map(Number);
const a = {
...fn(),
};
const a = fn();
Checkout in 🐊Putout Editor.
[
...[
...a,
...b,
],
...x,
];
[
...a,
...b,
...x,
];
MIT