Javascript – Expected to return a value at the end of arrow function error

I have this error Expected to return a value at the end of arrow function consistent-return. Im not sure how I can prevent this.

Im trying to stop the Swiper carousel when the screen-size is below 1060px

    import Swiper from 'swiper';
    export default function () {
      let articlesGalleryCarousel;
      const doSomething = () => {
        const enableSwiper = () => {
          articlesGalleryCarousel = new Swiper('.js-swiper-container', {
            loop: true,
            slidesPerView: 'auto',
            centeredSlides: true,
            a11y: true,
            keyboardControl: true,
            grabCursor: true,
            pagination: '.swiper-pagination',
            paginationClickable: true,
            navigation: {
              nextEl: '.carousel-button--prev',
              prevEl: '.carousel-button--next',
        const breakpoint = window.matchMedia('(max-width:1060px)');
        const breakpointChecker = () => {
          if (breakpoint.matches === true) {
            if (articlesGalleryCarousel !== undefined) articlesGalleryCarousel.destroy(true, true);
          } else if (breakpoint.matches === false) {
            return enableSwiper();
        breakpoint.addListener(breakpointChecker);
        breakpointChecker();
      return doSomething;
Related Solutions
Javascript – Set a default parameter value for a JavaScript function

From ES6/ES2015, default parameters are in the language specification.
function read_file(file, delete_after = false) {
  // Code
just works.
Reference: Default Parameters - MDN
  
Default function parameters allow formal parameters to be initialized with default values if no value or undefined is passed.
You can also simulate default named parameters via destructuring:
// the `= {}` below lets you call the function without any parameters
function myFor({ start = 5, end = 1, step = -1 } = {}) { // (A)
    // Use the variables `start`, `end` and `step` here
Pre ES2015,
There are a lot of ways, but this is my preferred method — it lets you pass in anything you want, including false or null. (typeof null == "object")
function foo(a, b) {
  a = typeof a !== 'undefined' ? a : 42;
  b = typeof b !== 'undefined' ? b : 'default_b';
    
Javascript – Get the values from the “GET” parameters (JavaScript)

JavaScript itself has nothing built in for handling query string parameters. 
Code running in a (modern) browser you can use the URL object (which is part of the APIs provided by browsers to JS):
var url_string = "http://www.example.com/t.html?a=1&b=3&c=m2-m3-m4-m5"; //window.location.href
var url = new URL(url_string);
var c = url.searchParams.get("c");
console.log(c);
For older browsers (including Internet Explorer), you can use this polyfill or the code from the original version of this answer that predates URL:
You could access location.search, which would give you from the ? character on to the end of the URL or the start of the fragment identifier (#foo), whichever comes first.
Then you can parse it with this:
function parse_query_string(query) {
  var vars = query.split("&");
  var query_string = {};
  for (var i = 0; i < vars.length; i++) {
    var pair = vars[i].split("=");
    var key = decodeURIComponent(pair[0]);
    var value = decodeURIComponent(pair[1]);
    // If first entry with this name
    if (typeof query_string[key] === "undefined") {
      query_string[key] = decodeURIComponent(value);
      // If second entry with this name
    } else if (typeof query_string[key] === "string") {
      var arr = [query_string[key], decodeURIComponent(value)];
      query_string[key] = arr;
      // If third or later entry with this name
    } else {
      query_string[key].push(decodeURIComponent(value));
  return query_string;
var query_string = "a=1&b=3&c=m2-m3-m4-m5";
var parsed_qs = parse_query_string(query_string);
console.log(parsed_qs.c);
You can get the query string from the URL of the current page with:
var query = window.location.search.substring(1);
var qs = parse_query_string(query);
            
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