54 lines
1.7 KiB
Plaintext
54 lines
1.7 KiB
Plaintext
---
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description: 'Disallow the `void` operator except when used to discard a value.'
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---
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> 🛑 This file is source code, not the primary documentation location! 🛑
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>
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> See **https://typescript-eslint.io/rules/no-meaningless-void-operator** for documentation.
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`void` in TypeScript refers to a function return that is meant to be ignored.
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The `void` operator is a useful tool to convey the programmer's intent to discard a value.
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For example, it is recommended as one way of suppressing [`@typescript-eslint/no-floating-promises`](./no-floating-promises.md) instead of adding `.catch()` to a promise.
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This rule helps an authors catch API changes where previously a value was being discarded at a call site, but the callee changed so it no longer returns a value.
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When combined with [no-unused-expressions](https://eslint.org/docs/rules/no-unused-expressions), it also helps _readers_ of the code by ensuring consistency: a statement that looks like `void foo();` is **always** discarding a return value, and a statement that looks like `foo();` is **never** discarding a return value.
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This rule reports on any `void` operator whose argument is already of type `void` or `undefined`.
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## Examples
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<!--tabs-->
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### ❌ Incorrect
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```ts
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void (() => {})();
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function foo() {}
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void foo();
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```
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### ✅ Correct
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```ts
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(() => {})();
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function foo() {}
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foo(); // nothing to discard
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function bar(x: number) {
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void x; // discarding a number
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return 2;
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}
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void bar(); // discarding a number
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```
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## Options
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### `checkNever`
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`checkNever: true` will suggest removing `void` when the argument has type `never`.
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## When Not To Use It
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If you don't mind extra `void`s in your project, you can avoid this rule.
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