index.js — react Source File

Source Code

/** @flow */

import * as React from 'react';
import {Fragment, useEffect, useRef, useState} from 'react';

// $FlowFixMe[missing-local-annot]
function WarnDuringRender({children = null}) {
  console.warn('This warning fires during every render');
  return children;
}

// $FlowFixMe[missing-local-annot]
function WarnOnMount({children = null}) {
  useEffect(() => {
    console.warn('This warning fires on initial mount only');
  }, []);
  return children;
}

// $FlowFixMe[missing-local-annot]
function WarnOnUpdate({children = null}) {
  const didMountRef = useRef(false);
  useEffect(() => {
    if (didMountRef.current) {
      console.warn('This warning fires on every update');
    } else {
      didMountRef.current = true;
    }
  });
  return children;
}

// $FlowFixMe[missing-local-annot]
function WarnOnUnmount({children = null}) {
  useEffect(() => {
    return () => {
      console.warn('This warning fires on unmount');
    };
  }, []);
  return children;
}

// $FlowFixMe[missing-local-annot]
function ErrorDuringRender({children = null}) {
  console.error('This error fires during every render');
  return children;
}

// $FlowFixMe[missing-local-annot]
function ErrorOnMount({children = null}) {
  useEffect(() => {
    console.error('This error fires on initial mount only');
  }, []);
  return children;
}

// $FlowFixMe[missing-local-annot]
function ErrorOnUpdate({children = null}) {
  const didMountRef = useRef(false);
  useEffect(() => {
// ... (148 more lines)