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class

url.URLSearchParams

class URLSearchParams

The URLSearchParams API provides read and write access to the query of a URL. The URLSearchParams class can also be used standalone with one of the four following constructors. The URLSearchParams class is also available on the global object.

The WHATWG URLSearchParams interface and the querystring module have similar purpose, but the purpose of the querystring module is more general, as it allows the customization of delimiter characters (& and =). On the other hand, this API is designed purely for URL query strings.

const myURL = new URL('https://example.org/?abc=123');
console.log(myURL.searchParams.get('abc'));
// Prints 123

myURL.searchParams.append('abc', 'xyz');
console.log(myURL.href);
// Prints https://example.org/?abc=123&abc=xyz

myURL.searchParams.delete('abc');
myURL.searchParams.set('a', 'b');
console.log(myURL.href);
// Prints https://example.org/?a=b

const newSearchParams = new URLSearchParams(myURL.searchParams);
// The above is equivalent to
// const newSearchParams = new URLSearchParams(myURL.search);

newSearchParams.append('a', 'c');
console.log(myURL.href);
// Prints https://example.org/?a=b
console.log(newSearchParams.toString());
// Prints a=b&a=c

// newSearchParams.toString() is implicitly called
myURL.search = newSearchParams;
console.log(myURL.href);
// Prints https://example.org/?a=b&a=c
newSearchParams.delete('a');
console.log(myURL.href);
// Prints https://example.org/?a=b&a=c
  • readonly size: number

    The total number of parameter entries.

  • name: string,
    value: string
    ): void;

    Append a new name-value pair to the query string.

  • name: string,
    value?: string
    ): void;

    If value is provided, removes all name-value pairs where name is name and value is value.

    If value is not provided, removes all name-value pairs whose name is name.

  • entries(): URLSearchParamsIterator<[string, string]>;

    Returns an ES6 Iterator over each of the name-value pairs in the query. Each item of the iterator is a JavaScript Array. The first item of the Array is the name, the second item of the Array is the value.

    Alias for urlSearchParams[@@iterator]().

  • fn: (this: TThis, value: string, name: string, searchParams: URLSearchParams) => void,
    thisArg?: TThis
    ): void;

    Iterates over each name-value pair in the query and invokes the given function.

    const myURL = new URL('https://example.org/?a=b&#x26;c=d');
myURL.searchParams.forEach((value, name, searchParams) => {
  console.log(name, value, myURL.searchParams === searchParams);
});
// Prints:
//   a b true
//   c d true
    @param fn

    Invoked for each name-value pair in the query

    @param thisArg

    To be used as this value for when fn is called

  • name: string
    ): null | string;

    Returns the value of the first name-value pair whose name is name. If there are no such pairs, null is returned.

    @returns

    or null if there is no name-value pair with the given name.

  • name: string
    ): string[];

    Returns the values of all name-value pairs whose name is name. If there are no such pairs, an empty array is returned.

  • name: string,
    value?: string
    ): boolean;

    Checks if the URLSearchParams object contains key-value pair(s) based on name and an optional value argument.

    If value is provided, returns true when name-value pair with same name and value exists.

    If value is not provided, returns true if there is at least one name-value pair whose name is name.

  • Returns an ES6 Iterator over the names of each name-value pair.

    const params = new URLSearchParams('foo=bar&#x26;foo=baz');
for (const name of params.keys()) {
  console.log(name);
}
// Prints:
//   foo
//   foo
  • name: string,
    value: string
    ): void;

    Sets the value in the URLSearchParams object associated with name to value. If there are any pre-existing name-value pairs whose names are name, set the first such pair's value to value and remove all others. If not, append the name-value pair to the query string.

    const params = new URLSearchParams();
params.append('foo', 'bar');
params.append('foo', 'baz');
params.append('abc', 'def');
console.log(params.toString());
// Prints foo=bar&#x26;foo=baz&#x26;abc=def

params.set('foo', 'def');
params.set('xyz', 'opq');
console.log(params.toString());
// Prints foo=def&#x26;abc=def&#x26;xyz=opq
  • sort(): void;

    Sort all existing name-value pairs in-place by their names. Sorting is done with a stable sorting algorithm, so relative order between name-value pairs with the same name is preserved.

    This method can be used, in particular, to increase cache hits.

    const params = new URLSearchParams('query[]=abc&#x26;type=search&#x26;query[]=123');
params.sort();
console.log(params.toString());
// Prints query%5B%5D=abc&#x26;query%5B%5D=123&#x26;type=search
  • toString(): string;

    Returns the search parameters serialized as a string, with characters percent-encoded where necessary.

  • Returns an ES6 Iterator over the values of each name-value pair.