NodeJS - urlSearchParams.keys() Method

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The NodeJS urlSearchParams.keys() method of class URLSearchParams returns an ES6 iterator that allows iteration through all the names of each name-value pair.

The URLSearchParams API provides methods that gives access to read and write the query of a URL. This class is also available on the global object.

Let’s consider a YouTube URL (‘https://www.youtube.com/watch?t=RS?f=TS&g=FR), where the portion after the ‘?’ is known as the query segment. In this query, (t) is the name, and (RS) is the value. Together it forms a name-value pair. There are three name-value pairs in the query string. So if we assign the query string to the key() method, it returns an ES6 iterator over the names of each name-value pair.

Syntax

Following is the syntax of the NodeJS URLSearchParams.keys() method

URLSearchParams.keys()

Parameters

This method does not accept any parameters.

Return Value

This method returns an ES6 iterator over the names of each name-value pair.

The following examples demonstrate the usage of the NodeJS URLSearchParams.keys() method:

Example

If the input URL string contains a query segment, the NodeJS urlSearchParams.keys() method returns an iterator over the names of name-value pairs from the query string.

In the following example, we are trying to get the names from the name-value pairs of the query string.

const url = require('node:url');

const MyUrl = new URL('https://www.tutorialspoint.com?Monday=1&Thursday=4&Friday=5');
console.log("URL: ", MyUrl.href);

const Params = new URLSearchParams('monday=1&thursday=4&friday=5');
console.log("Query string: " + Params);
console.log('All the names in the query string are: ');
for (const name of Params.keys()) {
    console.log(name);
}

Output

As we can see in the below output, the NodeJS keys() method returns all the names from the name-value pairs.

URL:  https://www.tutorialspoint.com/?Monday=1&Thursday=4&Friday=5
Query string: monday=1&thursday=4&friday=5
All the names in the query string are: 
monday
thursday
friday

Example

In the following example, we are appending some name-value pairs to the input query string. Then we are trying to get the names from the name-value pairs.

const url = require('node:url');

const Params = new URLSearchParams('Monday=1&Thursday=4&Friday=5');
console.log("Query string: " + Params);

Params.append('Saturday', 6);
Params.append('Sunday', 7);
console.log('All the names in the query string are: ');

for (const name of Params.keys()) {
    console.log(name);
}

Output

On executing the above program, it will generate the following output

Query string: Monday=1&Thursday=4&Friday=5
All the names in the query string are: 
Monday
Thursday
Friday
Saturday
Sunday