53 lines
790 B
Plaintext
53 lines
790 B
Plaintext
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---
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description: 'Require unary negation to take a number.'
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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-unsafe-unary-minus** for documentation.
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TypeScript does not prevent you from putting a minus sign before things other than numbers:
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```ts
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const s = 'hello';
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const x = -s; // x is NaN
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```
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This rule restricts the unary `-` operator to `number | bigint`.
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## Examples
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### ❌ Incorrect
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```ts
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declare const a: string;
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-a;
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declare const b: {};
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-b;
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```
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### ✅ Correct
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```ts
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-42;
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-42n;
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declare const a: number;
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-a;
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declare const b: number;
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-b;
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declare const c: number | bigint;
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-c;
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declare const d: any;
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-d;
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declare const e: 1 | 2;
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-e;
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```
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<!-- Intentionally Omitted: When Not To Use It -->
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