objectToQueryString javascript Code Snippet in 2025

Generates a query string from the key-value pairs of the given object.

• Use Array.prototype.reduce() on Object.entries(queryParameters) to create the query string.
• Determine the symbol to be either ? or & based on the length of queryString.
• Concatenate val to queryString only if it's a string.
• Return the queryString or an empty string when the queryParameters are falsy.

const objectToQueryString = queryParameters => {
  return queryParameters
    ? Object.entries(queryParameters).reduce(
        (queryString, [key, val], index) => {
          const symbol = queryString.length === 0 ? '?' : '&';
          queryString +=
            typeof val === 'string' ? `${symbol}${key}=${val}` : '';
          return queryString;
        },
        ''
      )
    : '';
};

objectToQueryString({ page: '1', size: '2kg', key: undefined });
// '?page=1&size=2kg'