String to slug in JS (wordpress sanitize_title)

string-to-slug.js

var string_to_slug = function (str)
{
	str = str.replace(/^\s+|\s+$/g, ''); // trim
	str = str.toLowerCase();

	// remove accents, swap ñ for n, etc
	var from = "àáäâèéëêìíïîòóöôùúüûñçěščřžýúůďťň·/_,:;";
	var to   = "aaaaeeeeiiiioooouuuuncescrzyuudtn------";

	for (var i=0, l=from.length ; i<l ; i++)
	{
		str = str.replace(new RegExp(from.charAt(i), 'g'), to.charAt(i));
	}

	str = str.replace('.', '-') // replace a dot by a dash 
		.replace(/[^a-z0-9 -]/g, '') // remove invalid chars
		.replace(/\s+/g, '-') // collapse whitespace and replace by a dash
		.replace(/-+/g, '-') // collapse dashes
		.replace( /\//g, '' ); // collapse all forward-slashes

	return str;
}

In typescript: https://gist.github.com/cleissonbarbosa/fc9951513051386eb053db6ccd737d4b

You can also do wp.url.cleanForSlug('Test Title'). Works in the frontend too. I used it to generate a table of contents section in the sidebar.

            jQuery(document).ready(function($) {
                var headings = $('.entry-content .wp-block-heading');
                if(headings.length == 0) {
                    $('.faq-post-contents').hide();
                }
                headings.each(function(index, element) {
                    var text = $(element).text();
                    var slug = $(element).attr('id');

                    //Create slug if not exists
                    if(!slug) {
                        slug = wp.url.cleanForSlug(text);
                        $(element).attr('id', slug);
                    }

                    $('.faq-post-contents ul').append('<li><a href="#'+slug+'">'+text+'</a></li>');
                });

            });