es-toolkit/dist/predicate/isJSON.mjs

A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

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