@shopify/react-hooks

@shopify/react-hooks

A collection of primitive React hooks.

Installation

$ yarn add @shopify/react-hooks

Usage

useOnValueChange()

This hook will track a given value and invoke a callback when it has changed.

function MyComponent({foo}: {foo: string}) {
  useOnValueChange(foo, (newValue, oldValue) => {
    console.log(`foo changed from ${oldValue} to ${newValue}`);
  });

  return null;
}

useTimeout()

This hook provides a declarative version of setTimeout(). The first argument is a callback that will be invoked after the given delay (number of milliseconds) as the second argument. Optionally, the timeout can be disabled by passing null as the delay.

function MyComponent() {
  const [status, setStatus] = React.useState('Pending');
  const pending = status === 'Pending';

  const buttonLabel = pending ? 'Cancel' : 'Reset';
  const handleClick = () => setStatus(pending ? 'Cancelled' : 'Pending');
  const delay = pending ? 1000 : null;

  useTimeout(() => setStatus('Fired'), delay);

  return (
    <div>
      <div>{status}</div>
      <button onClick={handleClick}>{buttonLabel}</button>
    </div>
  );
}

useInterval()

This hook provides a declarative version of setInterval. The first argument is a callback that will be invoked successively after the given delay (number of milliseconds) as the second argument. Optionally, the interval can be disabled by passing null as the delay.

function MyComponent() {
  const [counter, setCounter] = React.useState(0);
  const [enabled, setEnabled] = React.useState(true);

  const delay = enabled ? 1000 : null;
  const label = enabled ? 'Disable' : 'Enable';
  const toggle = () => setEnabled(!enabled);

  useInterval(() => setCounter(counter + 1), delay);

  return (
    <div>
      <div>{counter}</div>
      <button onClick={toggle}>{label}</button>
    </div>
  );
}

This is a TypeScript implementation of @gaeron's useInterval hook from the Overreacted blog post.

useLazyRef()

This hook creates a ref object like React’s useRef, but instead of providing it the value directly, you provide a function that returns the value. The first time the hook is run, it will call the function and use the returned value as the initial ref.current value. Afterwards, the function is never invoked. You can use this for creating refs to values that are expensive to initialize.

function MyComponent() {
  const ref = useLazyRef(() => someExpensiveOperation());

  React.useEffect(() => {
    console.log('Initialized expensive ref', ref.current);
  });

  return null;
}

useMountedRef()

This hook keeps track of a component's mounted / un-mounted status and returns a ref object like React’s useRef with a boolean value representing said status. This is often used when a component contains an async task that sets state after the task has resolved.

import React from 'react';
import {useMountedRef} from '@shopify/react-hooks';

function MockComponent() {
  const [result, setResult] = React.useState();
  const mounted = useMountedRef();

  async function handleOnClick() {
    const result = await fetchData();

    if (mounted.current) {
      setData(result);
    }
  }

  return (
    <button onClick={handleOnClick} type="button">
      Fetch Data
    </button>
  );
}

usePrevious()

This hook will store the previous value of a given variable.

function Score({value}) {
  const previousValue = usePrevious(value);
  const newRecord = value > previousValue ? <p>We have a new record!</p> : null;

  return (
    <>
      <p>Current score: {value}</p>
      {newRecord}
    </>
  );
}

useToggle()

This hook will provide an object that contains a boolean state value and a set of memoised callbacks to toggle it, force it to true and force it to false. It accepts one argument that is the initial value of the state. This is useful for toggling the active state of modals and popovers.

function MyComponent() {
  const {
    value: isActive,
    toggle: toggleIsActive,
    setTrue: setIsActiveTrue,
    setFalse: setIsActiveFalse,
  } = useToggle(false);
  const activeText = isActive ? 'true' : 'false';

  return (
    <>
      <p>Value: {activeText}</p>
      <button onClick={toggleIsActive}>Toggle isActive state</button>
      <button onClick={setIsActiveTrue}>Set isActive state to true</button>
      <button onClick={setIsActiveFalse}>Set isActive state to false</button>
    </>
  );
}