41 lines
1.2 KiB
JavaScript
41 lines
1.2 KiB
JavaScript
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//#region src/predicate/isJSON.ts
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/**
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* Checks if a given value is a valid JSON string.
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*
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* A valid JSON string is one that can be successfully parsed using `JSON.parse()`. According to JSON
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* specifications, valid JSON can represent:
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* - Objects (with string keys and valid JSON values)
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* - Arrays (containing valid JSON values)
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* - Strings
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* - Numbers
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* - Booleans
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* - null
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*
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* String values like `"null"`, `"true"`, `"false"`, and numeric strings (e.g., `"42"`) are considered
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* valid JSON and will return true.
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*
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* This function serves as a type guard in TypeScript, narrowing the type of the argument to `string`.
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*
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* @param {unknown} value The value to check.
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* @returns {boolean} Returns `true` if `value` is a valid JSON string, else `false`.
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*
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* @example
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* isJSON('{"name":"John","age":30}'); // true
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* isJSON('[1,2,3]'); // true
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* isJSON('true'); // true
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* isJSON('invalid json'); // false
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* isJSON({ name: 'John' }); // false (not a string)
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* isJSON(null); // false (not a string)
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*/
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function isJSON(value) {
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if (typeof value !== "string") return false;
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try {
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JSON.parse(value);
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return true;
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} catch {
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return false;
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}
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}
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//#endregion
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exports.isJSON = isJSON;
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