URLSearchParams: URLSearchParams() constructor

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.

Note: This feature is available in Web Workers.

The URLSearchParams() constructor creates and returns a new URLSearchParams object.

Syntax

js
new URLSearchParams()
new URLSearchParams(options)

Parameters

options Optional

One of:

  • A string, which will be parsed from application/x-www-form-urlencoded format. A leading '?' character is ignored. This is the only form that decodes percent-encoding, and decodes + to U+0020 SPACE.
  • A literal sequence of name-value string pairs, or any object — such as a FormData object — with an iterator that produces a sequence of string pairs. Note that File entries will be serialized as [object File] rather than as their filename (as they would in an application/x-www-form-urlencoded form).
  • A record of string keys and string values. Note that nesting is not supported.

Return value

A URLSearchParams object instance.

Examples

The following example shows how to create a URLSearchParams object from various inputs.

js
// Retrieve params via url.search, passed into constructor
const url = new URL("https://example.com?foo=1&bar=2");
const params1 = new URLSearchParams(url.search);

// Get the URLSearchParams object directly from a URL object
const params1a = url.searchParams;

// Pass in a string literal
const params2 = new URLSearchParams("foo=1&bar=2");
const params2a = new URLSearchParams("?foo=1&bar=2");

// Pass in a sequence of pairs
const params3 = new URLSearchParams([
  ["foo", "1"],
  ["bar", "2"],
]);

// Pass in a record
const params4 = new URLSearchParams({ foo: "1", bar: "2" });

This example shows how to build a new URL with an object of search parameters from an existing URL that has search parameters.

js
const url = new URL("https://example.com/?a=hello&b=world");

console.log(url.href);
// https://example.com/?a=hello&b=world

console.log(url.origin);
// https://example.com

const add_params = {
  c: "a",
  d: 2,
  e: false,
};

const new_params = new URLSearchParams([
  ...Array.from(url.searchParams.entries()), // [["a","hello"],["b","world"]]
  ...Object.entries(add_params), // [["c","a"],["d",2],["e",false]]
]).toString();
console.log(new_params);
// a=hello&b=world&c=a&d=2&e=false

const new_url = new URL(`${url.origin}${url.pathname}?${new_params}`);

console.log(new_url.href);
// https://example.com/?a=hello&b=world&c=a&d=2&e=false

// Here it is as a function that accepts (URL, Record<string, string>)
const addSearchParams = (url, params = {}) =>
  new URL(
    `${url.origin}${url.pathname}?${new URLSearchParams([
      ...Array.from(url.searchParams.entries()),
      ...Object.entries(params),
    ])}`,
  );

Specifications

Specification
URL
# dom-urlsearchparams-urlsearchparams

Browser compatibility