23 lines
809 B
TypeScript
23 lines
809 B
TypeScript
/**
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* Checks if a given value is null or undefined.
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*
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* This function tests whether the provided value is either `null` or `undefined`.
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* It returns `true` if the value is `null` or `undefined`, and `false` otherwise.
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*
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* This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to `null` or `undefined`.
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*
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* @param {any} x - The value to test for null or undefined.
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* @returns {x is null | undefined} `true` if the value is null or undefined, `false` otherwise.
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*
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* @example
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* const value1 = null;
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* const value2 = undefined;
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* const value3 = 42;
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* const result1 = isNil(value1); // true
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* const result2 = isNil(value2); // true
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* const result3 = isNil(value3); // false
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*/
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declare function isNil(x: any): x is null | undefined;
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export { isNil };
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