pve-eslint/eslint/docs/rules/prefer-object-spread.md
Thomas Lamprecht 6f03646270 import 7.12.1 upstream release
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
2020-10-29 11:42:45 +01:00

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# Prefer use of an object spread over `Object.assign` (prefer-object-spread)
When Object.assign is called using an object literal as the first argument, this rule requires using the object spread syntax instead. This rule also warns on cases where an `Object.assign` call is made using a single argument that is an object literal, in this case, the `Object.assign` call is not needed.
Introduced in ES2018, object spread is a declarative alternative which may perform better than the more dynamic, imperative `Object.assign`.
## Rule Details
Examples of **incorrect** code for this rule:
```js
/*eslint prefer-object-spread: "error"*/
Object.assign({}, foo)
Object.assign({}, {foo: 'bar'})
Object.assign({ foo: 'bar'}, baz)
Object.assign({ foo: 'bar' }, Object.assign({ bar: 'foo' }))
Object.assign({}, { foo, bar, baz })
Object.assign({}, { ...baz })
// Object.assign with a single argument that is an object literal
Object.assign({});
Object.assign({ foo: bar });
```
Examples of **correct** code for this rule:
```js
/*eslint prefer-object-spread: "error"*/
Object.assign(...foo);
// Any Object.assign call without an object literal as the first argument
Object.assign(foo, { bar: baz });
Object.assign(foo, Object.assign(bar));
Object.assign(foo, { bar, baz })
Object.assign(foo, { ...baz });
```
## When Not To Use It
This rule should not be used unless ES2018 is supported in your codebase.