How to get all query string parameters as an object in JavaScript

In vanilla JavaScript, there is no direct way to convert a query string into an object. However, you can use the URLSearchParams interface to parse a query string and then iterate over all keys to create an object.

Let us write a function that takes in a query string as a parameter and returns an object of all query string parameters:

const parseParams = (querystring) => {

    // parse query string
    const params = new URLSearchParams(querystring);

    const obj = {};

    // iterate over all keys
    for (const key of params.keys()) {
        if (params.getAll(key).length > 1) {
            obj[key] = params.getAll(key);
        } else {
            obj[key] = params.get(key);
        }
    }

    return obj;
};

To use the above function in browsers, you can do the following:

parseParams(window.location.search);

Alternatively, you can create a new URL object to retrieve the query string, and pass it to the parseParams() function:

// create new URL object
const url = new URL('http://example.com?size=M&size=XL&price=29&sort=desc');

// parse query parameters to object
console.log(parseParams(url.search));

You should see the following output:

{
    "size": [
        "M",
        "XL"
    ],
    "price": "29",
    "sort": "desc"
}

Take a look at this article to learn more about how to convert an object to a query string in vanilla JavaScript.

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