localStorage polyfill for jest #jest #localStorage

readme.md

localStorage for jest

Edit jor package.json and add

"setupFiles": [
      "<rootDir>/MYPATH/polyfills.js"
],

Your test file should look like

describe(Component.name, () => {
    it('should save to localStorage', () => {
        const KEY = 'foo';
        const VALUE = 'bar';
        localStorage.setItem(KEY, VALUE);
        // Or localStorage[KEY] = VALUE;
        expect(localStorage.getItem(KEY)).toBe(VALUE);
    });
});

polyfills.js

global.localStorage = {
    getItem(key) {
        return this[key];
    },
    setItem(key, value) {
        this[key] = value;
    },
    removeItem(key) {
        delete this[key];
    },
    get(key) {
        return this[key];
    },
    set(key, value) {
        this[key] = value;
    },
};