@jameslnewell/react-promise

@jameslnewell/react-promise

React hooks for working with promises.

If you need to work with promises, try @jameslnewell/react-observable.

Installation

NPM:

npm install @jameslnewell/react-promise

Yarn:

yarn add @jameslnewell/react-promise

Usage

You'll find a working example of react-promise in CodeSandbox.

usePromise

Start resolving a promise immediately e.g. fetch data from the server when a component is mounted

import React from 'react';
import {usePromise} from '@jameslnewell/react-promise';

const getUser = async (id) => {
  const res = await fetch(`/user/${id}`, {method: 'GET'});
  const data = await res.json();
  return data;
};

const UserProfile = ({id}) => {
  const [user, {status}] = usePromise(() => getUsername(id), [id]);
  switch (status) {
    case 'pending':
      return <>Loading...</>;
    case 'fulfilled':
      return (
        <>
          Hello <strong>{user.name}</strong>!
        </>
      );
    case 'rejected':
      return (
        <>
          Sorry, we couldn't find that user.
        <>
      );
  }
};

useInvokablePromise

Start resolving a promise when triggered e.g. change data on the server after the user clicks a button

import React, {useState, useEffect} from 'react';
import {useInvokablePromise} from '@jameslnewell/react-promise';

const putUser = async (id, data) => {
  await fetch(`/user/${id}`, {
    method: 'POST',
    body: JSON.stringify(data),
  });
};

const EditUserProfile = ({id}) => {
  const input = React.useRef(null);
  const [save, , {isPending}] = useInvokablePromise(data => putUser(id, data), [
    id,
  ]);
  const handleSave = async event => save(id, {name: input.current.value});
  return (
    <>
      <input ref={input} />
      <button disabled={isPending} onClick={handleSave}>
        Save
      </button>
    </>
  );
};

API

usePromise()

Immediately executes an operation.

Parameters:

• fn - A function that returns the promise to be fulfilled.
• deps - Any value that the function is dependent on and should trigger a new promise to be resolved.

Returns:

• [0] - The value returned by the operation.
• [1].status - Whether the promise is pending, fulfilled or rejected.
• [1].error - The reason why the promise was rejected.
• [1].isPending - Whether we're waiting for the promise to be fulfilled or rejected.
• [1].isFulfilled - Whether the promise has been fulfilled.
• [1].isRejected- Whether the promise has rejected

useInvokablePromise()

Executes an operation when the invoke method is called.

Parameters:

• fn - A function that returns the observable to be observed.
• deps - Any value that the function is dependent on and should trigger a new subscription on a new promise.

Returns:

• [0] - A function to invoke the operation.
• [1] - The value returned by the operation.
• [2].status - Whether the promise is pending, fulfilled or rejected.
• [2].error - The reason why the promise was rejected.
• [2].isPending - Whether we're waiting for the promise to be fulfilled or rejected.
• [2].isFulfilled - Whether the promise has been fulfilled.
• [2].isRejected- Whether the promise has rejected