How do I deal with localStorage in jest tests?

Question

I keep getting \"localStorage is not defined\" in Jest tests which makes sense but what are my options? Hitting brick walls.

Answer 1

To do the same in the Typescript, do the following:

Setup a file with the following contents:

let localStorageMock = (function() {
  let store = new Map()
  return {

    getItem(key: string):string {
      return store.get(key);
    },

    setItem: function(key: string, value: string) {
      store.set(key, value);
    },

    clear: function() {
      store = new Map();
    },

    removeItem: function(key: string) {
        store.delete(key)
    }
  };
})();
Object.defineProperty(window, 'localStorage', { value: localStorageMock });

Then you add the following line to your package.json under your Jest configs

"setupTestFrameworkScriptFile":"PATH_TO_YOUR_FILE",

Or you import this file in your test case where you want to mock the localstorage.