@financial-times/o-ads/src/js/utils/url.js

This package contains the core functionality used by the FT in providing ads across all of its sites. This includes ft.com, howtospendit.com, ftadviser.com and other specialist titles.

export const SEARCH_PARAMS = ['q', 'kw'];

/**
 * @typedef {{ [key: string]: string[] }} FilterDict
 */

/**
 * Remove unwanted params from nested query strings
 *
 * @param   {string}   nestedParams the URIencoded nested params
 * @param   {string[]} keysToStrip  the parameters to remove
 *
 * @return  {string}               [return description]
 */
export function filterNestedParams(nestedParams, keysToStrip) {
	if (!keysToStrip || keysToStrip.length < 1) {
		return nestedParams;
	}

	const childParams = new URLSearchParams(nestedParams);

	for (const key of keysToStrip) {
		childParams.delete(key);
	}

	return childParams.toString();
}

/**
 * Purge a URL of sensitive data in query strings
 *
 * Given the URL
 * ```url
 * https://www.ft.com/search?q=goog&cust_params=a%3D1%26b%3D2%26c%3D3%26d%3D4
 * ```
 * Supplying an object in the form
 * ```
 * {
 *   root: ['q', 'kw'],
 *   cust_params: ['a', 'c']
 * }
 * ```
 * will remove `q` from the main query string and `a`, `c` from the nested params
 * under `cust_params`:
 * ```url
 * https://www.ft.com/search?cust_params=b=2%26d%3D4
 * ```
 *
 * @param   {Object}  params
 * @param   {string | Location}  params.href     The base URL or `window.location`
 * @param   {FilterDict}         params.filters  The dictionary of params to be removed
 *
 * @return  {string}              A URL that has been stripped of the supplied params
 */
export function stripUrlParams({ href, filters }) {
	// @ts-ignore: URL absolutely accepts Location!
	const url = new URL(href);

	for (const [param, filter] of Object.entries(filters)) {
		if (param === 'root') {
			// Strip parameters from the main query string
			for (const key of filter) {
				url.searchParams.delete(key);
			}
		} else {
			// Handle nested parameters
			const nestedParams = url.searchParams.get(param);
			if (nestedParams) {
				url.searchParams.set(param, filterNestedParams(nestedParams, filter));
			}
		}
	}

	return url.href;
}