Change event fires extra times before IME composition ends

[chenxsan]

Extra details

• Similar discussion with extra details and reproducing analysis: Composition Events(Chinese, Japanese IME) problem in controlled components(input, textarea) #8683
• Previous attempt to fix it: Handle composition events in ChangeEventPlugin #8438 (includes some unit tests, but sufficient to be confident in the fix)

---

Original Issue

When I was trying this example from https://facebook.github.io/react/blog/2013/11/05/thinking-in-react.html, any Chinese characters inputted by Chinese pinyin input method would fire too many renders like:

Actually I would expect those not to fire before I confirm the Chinese character.

Then I tried another kind of input method - wubi input method, I got this:

It's weird too. So I did a test in jQuery:

Only after I press the space bar to confirm the character, the keyup event would fire.

I know it might be different between the implementation of jQuery keyup and react onChange , but I would expect the way how jQuery keyup handles Chinese characters instead of react's onChange.

[sophiebits]

cc @salier :) – What should we do here?

[hellendag]

I think we should not fire onChange until the IME string is committed.

One way to handle this in ChangeEventPlugin would be to ignore all input events between compositionstart and compositionend, then use the input event immediately following compositionend.

I did some quick testing on OSX Chrome and Firefox with Simplified Pinyin and 2-Set Korean, and the event order and data seem correct enough. (I predict that we'll have problems with IE Korean, but we may get lucky.)

I think we may continue to see issues with alternative input methods like the Google Input Tools extension, but there may be workarounds for that.

[Bertg]

This also influences how dialectic characters are typed for latin languages. For example on OS X inserting an é will fail using an international keyboard. Even the long press e and then use variant are failing here.

Sorry this seems to not be related. My apologies.

[jasonslyvia]

Is there any update? Suffering from this issue too.

[sophiebits]

None currently – this is not a high priority for us right now. I'd be happy to look at a pull request if anyone dives into fixing this.

[pswai]

@salier It seems like IE does not fire input event after compositionend. I have tested on IE11 and Edge on Windows 10. It fires properly in Chrome and Firefox.

[suhaotian]

in ie 9, Change event fires too many times when inputing Chinese characters again

[zhaoyao91]

Hello, Facebook guys, in fact this issue causes a SERIOUS problem: we can't update input asynchronously with Chinese input.
For example, we can't use meteor reactive datasources or stores like redux, because they all feedback update asynchronously.
Here is a simplest example to show this problem, it use setTimeout to do async update:
https://jsfiddle.net/liyatang/bq6oss6z/1/

I really hope you can fix this quickly, so that we won't waste efforts to workaround it here and there and over and over again.

Thanks.

Here is my workaround. If anyone face the same problem, you can have a look

[eyesofkids]

I made a simple example to demo how to use compositionstart and compositionend events to prevent inputing Chinese IME on onchange event problem.
Here is the link: https://jsfiddle.net/eyesofkids/dcxvas28/8/

[zhaoyao91]

@eyesofkids nice work, this could be made as the default implementation of onChange for input, textarea ...

[suhaotian]

nice work !

[julen]

I was hitting the same issue and @eyesofkids' workaround works perfectly (thank you!).

After having the workaround in place, I was diving into React's source code to at least try to add a failing test for this —hoping to later add the expected behavior to the library— although it seems a bit complicated for someone unfamiliar with the internals.

Initially I was expecting that a test similar to what's already available for ChangeEventPlugin should work, i.e. simulating a native compositionStart/compositionUpdate and checking no onChange callback was fired; also checking onChange would only be fired once compositionEnd was simulated. However this doesn't seem to work.

Hence I was thinking that maybe checking for ChangeEventPlugin.extractEvents() would be a feasible approach, similar to what's done in the tests for SelectEventPlugin. Here for some reason I always get undefined when extracting the events though.
For reference, this is the test code I tried within ChangeEventPlugin-test.js:

  var EventConstants = require('EventConstants');
  var ReactDOMComponentTree = require('ReactDOMComponentTree');
  var topLevelTypes = EventConstants.topLevelTypes;

  function extract(node, topLevelEvent) {
    return ChangeEventPlugin.extractEvents(
      topLevelEvent,
      ReactDOMComponentTree.getInstanceFromNode(node),
      {target: node},
      node
    );
  }

  function cb(e) {
    expect(e.type).toBe('change');
  }
  var input = ReactTestUtils.renderIntoDocument(
    <input onChange={cb} value='foo' />
  );

  ReactTestUtils.SimulateNative.compositionStart(input);

  var change = extract(input, topLevelTypes.topChange);
  expect(change).toBe(null);

I'm afraid I don't know exactly how one is supposed to debug these tests—otherwise I'd have a clearer picture of what's going on. Any guidance on how to proceed or any other pointers would be highly appreciated.

[julen]

The workaround suddenly broke in Chrome 53+ and it seems it is not valid anymore because they changed the order compositionend is fired: previously it happened before textInput, now after textInput. As a consequence of this, change won't be fired if it is aborted while in composition 😕.

[suhaotian]

https://github.com/suhaotian/react-input maybe help someone

[eyesofkids]

There is a tricky solution for Chrome v53. To call the handlechange after compositionend is fired.

handleComposition  = (event) => {

    if(event.type === 'compositionend'){
      onComposition = false

      //fire change method to update for Chrome v53
      this.handleChange(event)

    } else{
      onComposition = true
    }
  }

check the demo here: https://jsfiddle.net/eyesofkids/dcxvas28/11/

[vincent714]

@chenxsan did you find out the solution?
you can detect the compositionStart and let a variable equal to true.
Then to use the variable, which you set, at onChange to see if it should fire the query

[RebaekSoparkKitchen]

any updates?

Hi, I face the same issue when I want to do some operation in handleChange function, and my solution is just use composition event to handle it.

If it works for you, extract it to hooks and we use reuse it easily.

import React, { useState } from 'react';

export default function Solution() {
  const [value, setValue] = useState('');
  const [onComposition, setOnComposition] = useState(false);

  function handleComposition(event) {
    if (event.type === 'compositionstart') {
      setOnComposition(true);
    }
    if (event.type === 'compositionend') {
      setOnComposition(false);
    }
  }
  function handleChange(e) {
    let temp = e.target.value;
    if (!onComposition) {
      // any operation you want to do...
      temp = temp.replace(/z/g, 'Z');
    }
    setValue(temp);
  }

  return (
    <input
      onChange={handleChange}
      value={value}
      onCompositionStart={handleComposition}
      onCompositionEnd={handleComposition}
    />
  );
}

[krmao]

also this code https://zhuanlan.zhihu.com/p/415365117

[eyesofkids]

also this code https://zhuanlan.zhihu.com/p/415365117

A simpler component:

// refs: https://zhuanlan.zhihu.com/p/415365117

import { useRef, useState, forwardRef } from 'react'

function InputIME(props, ref) {
  const { onChange, value, ...otherProps } = props

  // log if on composition
  const onComposition = useRef(false)
  // temp input
  const [inputValue, setInputValue] = useState('')

  const _onChange = (event) => {
    setInputValue(event.target.value)

    // IME method start
    if (event.type === 'compositionstart') {
      onComposition.current = true
      return
    }

    // IME method end
    if (event.type === 'compositionend') {
      onComposition.current = false
    }

    // handle parent onChange
    if (!onComposition.current) {
      onChange(event)
    }
  }

  return (
    <input
      {...otherProps}
      ref={ref}
      value={inputValue}
      onChange={_onChange}
      onCompositionEnd={_onChange}
      onCompositionStart={_onChange}
    />
  )
}

export default forwardRef(InputIME)

[kamikat]

Another hook-ish workaround:

import { useEffect, useState, useRef } from "react";

export function useAsyncInputRef<T extends HTMLElement & { value: string }>(
  value: string,
  forwardRef?: React.RefObject<T>
) {
  const [compositionFlag, setComposition] = useState(false);
  const newRef = useRef<T>(null);
  const ref = forwardRef || newRef;

  useEffect(() => {
    const el = ref.current;
    if (el) {
      const compositionStart = () => setComposition(true);
      const compositionEnd = () => setComposition(false);
      el.addEventListener("compositionstart", compositionStart);
      el.addEventListener("compositionend", compositionEnd);
      return () => {
        el.removeEventListener("compositionstart", compositionStart);
        el.removeEventListener("compositionend", compositionEnd);
        setComposition(false);
      };
    }
  }, [ref]);

  useEffect(() => {
    if (ref.current && compositionFlag === false) {
      ref.current.value = value;
    }
  }, [compositionFlag, value, ref]);

  return ref;
}

render(
  <input
    type="text"
    ref={useAsyncInputRef(value)}
    onChange={(e) => setValue(e.target.value)}
  />
);

Live demo: https://codepen.io/kamikat/pen/OJwMJLr

[17x]

Here is another one implementation:

interface Props extends React.InputHTMLAttributes<HTMLInputElement> {
  onChange: (e) => void;
  onRealChange?: (e) => void;
  comp?: React.FunctionComponent;
}

const CompositionEventInput: FC<Props> = ({
  onChange,
  onRealChange,
  comp: Comp,
  ...rest
}: Props) => {
  const [isComposition, setIsComposition] = useState(false);
  const [value, setValue] = useState("");

  const common = (e) => {
    const { type } = e;

    switch (type) {
      case "compositionstart":
        setIsComposition(true);
        break;

      case "compositionend":
        if (isComposition) {
          onChange(e);
        }

        setIsComposition(false);
        break;

      case "change":
        const newValue = e.target.value.trim();

        setValue(newValue);

        if (onRealChange) {
          onRealChange(newValue);
        }

        if (!isComposition) {
          onChange(e);
        }
        break;
    }
  };

  const events: Partial<HTMLAttributes<Function>> = {
    onKeyDown: common,
    onKeyUp: common,
    onCompositionEnd: common,
    onCompositionStart: common,
    onCompositionUpdate: common,
    onChange: common
  };

  const props = {
    value,
    ...events
  };

  if (Comp) {
    return <Comp {...props} />;
  }

  // @ts-ignore
  return <input {...props} {...rest} />;
};

CodeSandBox DEMO Link

[zheeeng]

Is there an official improvement plan for this? I'm suffering from using workarounds anywhere.

[weihong1028]

Nice,thank you！                               ——weihong

[lethi2k]

import React, { useState } from 'react';

export default function Solution() {
  const [onComposition, setOnComposition] = useState(false);

  function handleComposition(event) {
    if (event.type === 'compositionstart') {
      setOnComposition(true);
    }
    if (event.type === 'compositionend') {
      setOnComposition(false);
    }
  }
  function onPressEnter(e) {
    if (!onComposition) {
       // code here
    }
  }

  return (
    <input
      onPressEnter={onPressEnter}
      value={value}
      onCompositionStart={handleComposition}
      onCompositionEnd={handleComposition}
    />
  );
}

[weihong1028]

Nice,thank you！                               ——weihong