31 lines
647 B
Plaintext
31 lines
647 B
Plaintext
import type {WritableKeysOf} from './writable-keys-of';
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/**
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Extract all readonly keys from the given type.
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This is useful when you want to create a new type that contains readonly keys only.
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@example
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```
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import type {ReadonlyKeysOf} from 'type-fest';
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interface User {
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name: string;
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surname: string;
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readonly id: number;
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}
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type UpdateResponse<Entity extends object> = Pick<Entity, ReadonlyKeysOf<Entity>>;
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const update1: UpdateResponse<User> = {
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id: 123,
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};
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```
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@category Utilities
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*/
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export type ReadonlyKeysOf<T> =
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T extends unknown // For distributing `T`
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? Exclude<keyof T, WritableKeysOf<T>>
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: never; // Should never happen
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