Author: John Au-Yeung

Sometimes, we want to dispatch multiple actions in Redux and JavaScript.

In this article, we’ll look at how to dispatch multiple actions in Redux and JavaScript.

How to dispatch multiple actions in Redux and JavaScript?

To dispatch multiple actions in Redux and JavaScript, we call dispatch multiple times.

For instance, we write

const action1 = (id) => {
  return (dispatch) => {
    dispatch(action2(id));
    dispatch(action3(id));
  };
};

to call dispatch with all the actions we want to dispatch in the function returned by action1.

Conclusion

To dispatch multiple actions in Redux and JavaScript, we call dispatch multiple times.

Sometimes, we want to fix JavaScript error "val.match is not a function"

In this article, we’ll look at how to fix JavaScript error "val.match is not a function".

How to fix JavaScript error "val.match is not a function"?

To fix JavaScript error "val.match is not a function", we should make sure val is a string.

For instance, we write

const val = 12;

if (String(val).match(/^s+$/) || val === "") {
  console.log("success: ", val);
}

to call String with val to convert it to a string.

Then we call match on the returned string.

Conclusion

To fix JavaScript error "val.match is not a function", we should make sure val is a string.

Sometimes, we want to spy on function with Jest and JavaScript.

In this article, we’ll look at how to spy on function with Jest and JavaScript.

How to spy on function with Jest and JavaScript?

To spy on function with Jest and JavaScript, we use the spyOn method.

For instance, we write

import { mount } from "enzyme";

describe("My component", () => {
  it("should call getData", () => {
    const spy = jest.spyOn(Component.prototype, "getData");
    mount(<Component />);
    expect(spy).toHaveBeenCalledTimes(1);
  });
});

to call spyOn on the Component‘s getData instance method with spyOn.

Then we call mount to mount the Component.

And then we call toHaveBeenCalledTimes with 1 to check if getData has been called once.

Conclusion

To spy on function with Jest and JavaScript, we use the spyOn method.