Convert object to json string

78.0% acceptance

Mar 31, 2026

209

Given a value, return a valid JSON string of that value. The value can be a string, number, array, object, boolean, or null. The returned string should not include extra spaces. The order of keys should be the same as the order returned by Object.keys(). Please solve it without using the built-in JSON.stringify method.

Solution

TypeScript

Time O(1)

Space O(1)

LeetCode

solution.ts

type JSONValue = null | boolean | number | string | JSONValue[] | { [key: string]: JSONValue };

function jsonStringify(object: JSONValue): string {
  if (object === null) return 'null';
  if (typeof object === 'boolean') return String(object);
  if (typeof object === 'number') return String(object);
  if (typeof object === 'string') return '"' + object + '"';
  if (Array.isArray(object)) {
    return '[' + object.map(jsonStringify).join(',') + ']';
  }
  const entries = Object.keys(object).map(key => '"' + key + '"' + ':' + jsonStringify(object[key]));
  return '{' + entries.join(',') + '}';
};