28 lines
1.1 KiB
TypeScript
28 lines
1.1 KiB
TypeScript
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/**
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* @license
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* Copyright 2021 Google LLC
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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type Falsy = null | undefined | false | 0 | -0 | 0n | '';
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/**
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* When `condition` is true, returns the result of calling `trueCase()`, else
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* returns the result of calling `falseCase()` if `falseCase` is defined.
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*
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* This is a convenience wrapper around a ternary expression that makes it a
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* little nicer to write an inline conditional without an else.
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*
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* @example
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*
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* ```ts
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* render() {
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* return html`
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* ${when(this.user, () => html`User: ${this.user.username}`, () => html`Sign In...`)}
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* `;
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* }
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* ```
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*/
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export declare function when<C extends Falsy, T, F = undefined>(condition: C, trueCase: (c: C) => T, falseCase?: (c: C) => F): F;
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export declare function when<C, T, F>(condition: C extends Falsy ? never : C, trueCase: (c: C) => T, falseCase?: (c: C) => F): T;
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export declare function when<C, T, F = undefined>(condition: C, trueCase: (c: Exclude<C, Falsy>) => T, falseCase?: (c: Extract<C, Falsy>) => F): C extends Falsy ? F : T;
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export {};
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//# sourceMappingURL=when.d.ts.map
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