react-use-is-loading

React hook for determining if any specified part of your application state is loading.

This hook is for you if you...

• Want an easy way of knowing within a component if a given part of state is loading ✅

Installation

With NPM:

npm i --save react-use-is-loading

With Yarn:

yarn add react-use-is-loading

API

useIsLoading is a function that takes 2 parameters:

• fetchingFlag: this is the flag that you use in your Redux store in order to flag whether a slice of state is loading.
• keys: these are the keys (from your Redux store) that you want to check to see if they are loading.

How it works

• You call the hook with the parameters described above.
• You receive a boolean back that indicates whether any of the specified parts of state are loading.

Note: your Redux store must contain the fetching flag you specify for each slice of state AND it must be at the root of each slice (see usage section for more detail)

Usage

If your Redux store looks like this:

type State = {
  a: {
    foo: string;
    isFetching: boolean;
  };
  b: {
    bar: string;
    isFetching: boolean;
  };
  c: {
    baz: boolean;
    isFetching: boolean;
  };
};

And we assume that:

1. All root level slices of state (i.e. a, b and c) have an isFetching flag.
2. isFetching is set to true whilst data is fetching (i.e. an action has been dispatched to begin the data retrieval process).

We can then determine whether something is loading in a component like this:

In SomeComponent.tsx

import React from 'react';
import { useIsLoading } from 'react-use-is-loading';

const MyComponent = () => {
  const isLoading = useIsLoading('isFetching', ['a', 'b']);

  return isLoading ? <span>Loading...</span> : <div>Here is some content</div>;
};

export { MyComponent };

It's as simple as that. We have specified that the flag we use in our Redux store for tracking whether a slice of state has loaded (isFetching) and the keys of state that we want to track whether they have loaded (a and b). We render some loading content if they haven't loaded yet, else we load some other content.

Testing

The project uses Jest for testing, along with react-hooks-testing-library for rendering hooks without explicitly creating harness components.

Contributing

I welcome all contributions to this project. Please feel free to raise any issues or pull requests as you see fit :)