94 lines
3.1 KiB
Plaintext
94 lines
3.1 KiB
Plaintext
---
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description: 'Disallow calling a function with a value with type `any`.'
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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-argument** for documentation.
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The `any` type in TypeScript is a dangerous "escape hatch" from the type system.
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Using `any` disables many type checking rules and is generally best used only as a last resort or when prototyping code.
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Despite your best intentions, the `any` type can sometimes leak into your codebase.
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Calling a function with an `any` typed argument creates a potential safety hole and source of bugs.
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This rule disallows calling a function with `any` in its arguments.
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That includes spreading arrays or tuples with `any` typed elements as function arguments.
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This rule also compares generic type argument types to ensure you don't pass an unsafe `any` in a generic position to a receiver that's expecting a specific type.
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For example, it will error if you pass `Set<any>` as an argument to a parameter declared as `Set<string>`.
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## Examples
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<!--tabs-->
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### ❌ Incorrect
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```ts
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declare function foo(arg1: string, arg2: number, arg3: string): void;
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const anyTyped = 1 as any;
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foo(...anyTyped);
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foo(anyTyped, 1, 'a');
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const anyArray: any[] = [];
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foo(...anyArray);
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const tuple1 = ['a', anyTyped, 'b'] as const;
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foo(...tuple1);
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const tuple2 = [1] as const;
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foo('a', ...tuple, anyTyped);
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declare function bar(arg1: string, arg2: number, ...rest: string[]): void;
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const x = [1, 2] as [number, ...number[]];
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foo('a', ...x, anyTyped);
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declare function baz(arg1: Set<string>, arg2: Map<string, string>): void;
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foo(new Set<any>(), new Map<any, string>());
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```
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### ✅ Correct
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```ts
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declare function foo(arg1: string, arg2: number, arg3: string): void;
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foo('a', 1, 'b');
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const tuple1 = ['a', 1, 'b'] as const;
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foo(...tuple1);
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declare function bar(arg1: string, arg2: number, ...rest: string[]): void;
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const array: string[] = ['a'];
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bar('a', 1, ...array);
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declare function baz(arg1: Set<string>, arg2: Map<string, string>): void;
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foo(new Set<string>(), new Map<string, string>());
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```
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<!--/tabs-->
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There are cases where the rule allows passing an argument of `any` to `unknown`.
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Example of `any` to `unknown` assignment that are allowed:
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```ts showPlaygroundButton
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declare function foo(arg1: unknown, arg2: Set<unknown>, arg3: unknown[]): void;
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foo(1 as any, new Set<any>(), [] as any[]);
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```
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## When Not To Use It
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If your codebase has many existing `any`s or areas of unsafe code, it may be difficult to enable this rule.
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It may be easier to skip the `no-unsafe-*` rules pending increasing type safety in unsafe areas of your project.
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You might consider using [ESLint disable comments](https://eslint.org/docs/latest/use/configure/rules#using-configuration-comments-1) for those specific situations instead of completely disabling this rule.
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## Related To
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- [`no-explicit-any`](./no-explicit-any.md)
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- [`no-unsafe-assignment`](./no-unsafe-assignment.md)
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- [`no-unsafe-call`](./no-unsafe-call.md)
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- [`no-unsafe-member-access`](./no-unsafe-member-access.md)
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- [`no-unsafe-return`](./no-unsafe-return.md)
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