2024 05 13 calling a function in react component from another component issue - bizkite-co/handterm GitHub Wiki

original file name: Codeium Chat - scoh0D11BEgOn3NJ96UzbmwU7P62Y6f5.md summary: The user is seeking guidance on calling a function in a React component (testInput() in NextCharsDisplay) from another component (XtermAdapter). The user initially attempted to use this.setState() in XtermAdapter but encountered a warning about calling setState on an unmounted component.

I provided suggestions on how to accomplish this within React's standard methodology, including using refs, callbacks, and state management with hooks. The user then shared an error message indicating that the problem lies in calling this.setState() in XtermAdapter, specifically when setting isInPhraseMode to true.

I explained that the warning likely occurs from calling setState before the component mounts and provided a correct way to initialize state within a React component. I pointed out that calling setState from the constructor could lead to this warning and suggested using lifecycle methods like componentDidMount for state updates after mounting.

The user shared the relevant code snippet from XtermAdapter.tsx, highlighting the problematic line calling this.setState({ isInPhraseMode: true }). I recommended adjusting state updates within lifecycle methods or where the component is fully mounted to avoid the warning about unmounted components.

If the issue persists, I offered further assistance upon reviewing the complete XtermAdapter code or specified sections. date: 2024-05-13T14:15

Codeium Chat Conversation

Note: This is purely the output of the chat conversation and does not contain any raw data, codebase snippets, etc. used to generate the output.

User at 2:15 pm, May 13, 2024

I want to call testInput() in NextCharsDisplay from XternAdapter and I am not sure how to do that.

Codeium at 2:15 pm, May 13, 2024

To call testInput() in NextCharsDisplay from XtermAdapter, you need to have an instance of NextCharsDisplay within XtermAdapter. From the provided context, it seems that NextCharsDisplay is a class component, and you are already rendering it in XtermAdapter using the renderNextCharsdisplay method.

If you need to call the testInput() method directly, you should ensure that you have a reference to the NextCharsDisplay instance. However, the context does not provide enough information to determine if you currently have such a reference in XtermAdapter. If you do not have a reference to the NextCharsDisplay instance, you would need to create one.

Here's a general approach to how you might set up a reference to NextCharsDisplay and call the testInput() method:

  1. Create a property within XtermAdapter to hold the reference to NextCharsDisplay.
  2. Assign the NextCharsDisplay instance to the property when you create it.
  3. Call the testInput() method on the NextCharsDisplay reference when needed.

Here is an illustrative example:

class XtermAdapter {
  // Other properties and methods...

  private nextCharsDisplay: NextCharsDisplay | null = null;

  constructor(/* parameters */) {
    // Constructor implementation...
    this.initNextCharsDisplay();
  }

  private initNextCharsDisplay() {
    this.nextCharsDisplay = new NextCharsDisplay(/* props */);
    // You might need to mount the NextCharsDisplay component to the DOM or perform other setup steps here.
  }

  public triggerTestInput(data: string) {
    if (this.nextCharsDisplay) {
      this.nextCharsDisplay.testInput(data);
    }
  }

  // Other methods...
}

With this setup, you can call triggerTestInput from within XtermAdapter whenever you need to pass data to NextCharsDisplay's testInput() method.

If NextCharsDisplay is already instantiated and managed by React (as a component), you would need to lift the state up or use callbacks to manage the data flow. Given that you are in the process of migrating to React, the final implementation might look different as you move towards a more React-centric architecture.

Please provide the section of the code where NextCharsDisplay is instantiated or managed within XtermAdapter, and I can give a more precise answer.

User at 2:17 pm, May 13, 2024

I want to call the function the React way of calling functions in other components.

What are the best options for doing that in React-standard methodology?

Codeium at 2:17 pm, May 13, 2024

In React, components typically communicate via props and state. Methods in child components are generally called indirectly by setting props from the parent that trigger behavior in the child. Here are some React-standard methodologies for calling methods across components:

  1. Using Refs: If you need to call a method in a child component, React's ref attribute can be used to get a reference to the child component instance and call methods on it directly.
class ParentComponent extends React.Component {
  private childRef = React.createRef<ChildComponent>();

  callChildMethod = () => {
    // Make sure the ref is attached to the child component
    if (this.childRef.current) {
      this.childRef.current.someMethod();
    }
  };

  render() {
    return (
      <>
        <ChildComponent ref={this.childRef} />
        <button onClick={this.callChildMethod}>Call Child Method</button>
      </>
    );
  }
}

class ChildComponent extends React.Component {
  someMethod() {
    // Perform some action
  }

  render() {
    // Component render logic
  }
}
  1. Using Callbacks: For a more declarative approach, you can pass a callback function to the child component that it calls at the appropriate time.
class ParentComponent extends React.Component {
  handleChildAction = (data: string) => {
    // Do something with the data
  };

  render() {
    return <ChildComponent onAction={this.handleChildAction} />;
  }
}

class ChildComponent extends React.Component<{ onAction: (data: string) => void }> {
  render() {
    // When you want to call the method, you can do:
    this.props.onAction('some data');
    // Component render logic
  }
}
  1. Using State and Effect Hooks: In functional components, you can use state and effect hooks to react to changes and perform actions when certain conditions are met.
const ParentComponent = () => {
  const [trigger, setTrigger] = useState(false);

  // Call this function to trigger the child action
  const handleButtonClick = () => {
    setTrigger(true);
  };

  return (
    <>
      <ChildComponent trigger={trigger} setTrigger={setTrigger} />
      <button onClick={handleButtonClick}>Trigger Child Action</button>
    </>
  );
};

const ChildComponent = ({ trigger, setTrigger }: { trigger: boolean; setTrigger: (trigger: boolean) => void }) => {
  useEffect(() => {
    if (trigger) {
      // Perform the action
      console.log('Child action triggered');

      // Reset the trigger
      setTrigger(false);
    }
  }, [trigger, setTrigger]);

  return (
    // Child component render logic
  );
};

Given that you're working with XtermAdapter and have a NextCharsDisplay component rendered by it, you should decide which method suits your use case best. If NextCharsDisplay is a class component, you might want to use refs. If it’s a functional component, using state and effect hooks would be more appropriate.

Please provide more information about NextCharsDisplay (for example, whether it's a class or functional component) and how it’s used within XtermAdapter for a more specific implementation.

User at 2:56 pm, May 13, 2024

I'm getting this error in XtermAdapter

ns-hugo:C:\Users\xge…termAdapter.tsx:133  
Warning: Can't call setState on a component that is not yet mounted. This is a no-op, but it might indicate a bug in your application. Instead, assign to `this.state` directly or define a `state = {};` class property with the desired state in the XtermAdapter component.

Codeium at 2:57 pm, May 13, 2024

The warning you're seeing typically indicates that you're trying to call setState on a component instance before it has been fully mounted into the DOM. This can happen if you call setState in the constructor or during the initial setup of the component before the mounting phase.

In class components, the initial state should be set up directly on the state property or inside the constructor without using setState. Here's an example of setting the initial state correctly:

class XtermAdapter extends React.Component {
  constructor(props) {
    super(props);
    // Set the initial state directly. Do not use setState in the constructor.
    this.state = {
      isInPhraseMode: false,
      isActive: false,
    };
  }

  // Rest of the component code...
}

If you need to update the state based on props or some other calculations, do it directly within the constructor as shown above. Any state updates that occur after the component is mounted should be done using setState, typically in lifecycle methods like componentDidMount, componentDidUpdate, or event handlers.

Check your XtermAdapter code to ensure that setState is not being called during the initialization or constructor phase. If you have logic that needs to run before the component is mounted and it involves state updates, consider moving that logic to the componentDidMount lifecycle method, where it's safe to call setState.

class XtermAdapter extends React.Component {
  // ...

  componentDidMount() {
    // It's safe to call setState here
    this.setState({
      // ...state updates...
    });
  }

  // ...
}

If you're setting the state based on props, you can also use the getDerivedStateFromProps lifecycle method.

class XtermAdapter extends React.Component {
  static getDerivedStateFromProps(props, state) {
    // Return an object to update state, or null to update nothing
  }

  // ...
}

Make sure you are not calling setState in any method that might be invoked by the constructor. If you're still encountering issues, please provide the relevant section of the XtermAdapter code where the state is being set, and I can further assist you.

User at 3:01 pm, May 13, 2024

The error indicates that the problem is happening in this line:

   if (command === 'phrase') {
    this.setState({ isInPhraseMode: true });
   }

of the XtermAdapter.tsx:

// XtermAdapter.ts
import { Terminal } from '@xterm/xterm';
import { IHandexTerm } from './HandexTerm';
import { TerminalCssClasses } from './TerminalTypes';
import { IWebCam, WebCam } from '../utils/WebCam';
import React from 'react';
import ReactDOM from 'react-dom';
import { createRoot, Root } from 'react-dom/client';
import { NextCharsDisplay } from '../NextCharsDisplay';
import { createElement } from '../utils/dom';


export class XtermAdapter extends React.Component<any, any> {
 state = {
  isInPhraseMode: false,
  isActive: false,
 }
 private nextCharsDisplayRef: React.RefObject<NextCharsDisplay> = React.createRef(); 
  
 private terminal: Terminal;
 private terminalElement: HTMLElement;
 private lastTouchDistance: number | null = null;
 private currentFontSize: number = 17;
 private outputElement: HTMLElement;
 private videoElement: HTMLVideoElement;
 private promptDelimiter: string = '$';
 private promptLength: number = 0;
 private webCam: IWebCam;
 private isShowVideo: boolean = false;

 private nextCharsDisplayRoot: Root | null = null;

 private wholePhraseChords: HTMLElement | null = null;
 private isInPhraseMode: boolean = false;

 constructor(private handexTerm: IHandexTerm, private element: HTMLElement) {
  super({});
  this.terminalElement = element;
  this.terminalElement.classList.add(TerminalCssClasses.Terminal);
  this.videoElement = this.createVideoElement();
  this.webCam = new WebCam(this.videoElement);
  this.terminalElement.prepend(this.videoElement);
  this.wholePhraseChords = document.getElementById(TerminalCssClasses.WholePhraseChords) as HTMLElement;
  this.wholePhraseChords = createElement('div', TerminalCssClasses.WholePhraseChords);
  this.wholePhraseChords.hidden = true;
  // this.chordImageHolder.hidden = true;
  this.outputElement = this.createOutputElement();
  // this.terminalElement.prepend(this.nextCharsDisplay.timer.timerSvg)
  this.terminalElement.prepend(this.outputElement);
  this.terminalElement.prepend(this.wholePhraseChords);
  this.terminal = new Terminal({
   fontFamily: '"Fira Code", Menlo, "DejaVu Sans Mono", "Lucida Console", monospace',
   cursorBlink: true,
   cursorStyle: 'block'
  });
  this.terminal.open(element);
  this.terminal.onData(this.onDataHandler.bind(this));
  this.loadCommandHistory();
  this.setViewPortOpacity();
  this.addTouchListeners();
  this.loadFontSize();
  this.renderNextCharsdisplay();
 }

 setPhrase(phrase: string) {
  this.setState({ phrase: phrase });
 }
 renderNextCharsdisplay() {
  // Find or create a container element where you want to mount your React component.
  const container = document.getElementById(TerminalCssClasses.NextCharsRate) as HTMLElement;

  // Create a root and render your React component.
  // Check if a root has been created
  if (!this.nextCharsDisplayRoot) {
   // If not, create a root and save the reference
   this.nextCharsDisplayRoot = createRoot(container);
   // this.nextCharsDisplay.nextChars.style.float = 'left';
   // this.nextCharsDisplay.phrase.hidden = true;
   // this.nextCharsDisplay.isTestMode = true;
   // this.terminalElement.prepend(this.nextCharsDisplay.nextCharsRate);
  }

  // Now use the root to render your React component.
  this.nextCharsDisplayRoot.render(
   <NextCharsDisplay
    onNewPhraseSet={this.handleNewPhraseSet}
   />
  );
 }

 callChildTestInput = (testPhrase: string) => {
  if(this.nextCharsDisplayRef.current) this.nextCharsDisplayRef.current.updateDisplay(testPhrase);
 }
 wpmCallback = () => {
  console.log("Timer not implemented");
 }

 public onDataHandler(data: string): void {
  // Check if the Enter key was pressed
  if (data.charCodeAt(0) === 3) { // Ctrl+C
   this.isInPhraseMode = false;
   this.terminal.reset();
   this.prompt();
  } else if (data.charCodeAt(0) === 127) { // Backspace
   // Remove the last character from the terminal
   if (this.terminal.buffer.active.cursorX < this.promptLength) return;
   this.terminal.write('\x1b[D \x1b[D');
   // let cursorIndex = this.terminal.buffer.active.cursorX;
  }
  if (data.charCodeAt(0) === 13) { // Enter key
   // Process the command before clearing the terminal
   // TODO: cancel timer
   if(this.nextCharsDisplayRef.current) this.nextCharsDisplayRef.current.cancelTimer();
   let command = this.getCurrentCommand();
   // Clear the terminal after processing the command
   this.terminal.reset();
   // TODO: reset timer
   // Write the new prompt after clearing
   this.prompt();
   if (command === '') return;
   if (command === 'clear') {
    this.handexTerm.clearCommandHistory();
    this.outputElement.innerHTML = '';
    return;
   }
   if (command === 'video') {
    this.toggleVideo();
    let result = this.handexTerm.handleCommand(command + ' --' + this.isShowVideo);
    this.outputElement.appendChild(result);
    return;
   }
   if (command === 'phrase') {
    this.setState({ isInPhraseMode: true });
   }
   let result = this.handexTerm.handleCommand(command);
   this.outputElement.appendChild(result);
  } else if (this.isInPhraseMode) {
   this.terminal.write(data);
   let command = this.getCurrentCommand();
   if (command.length === 0) {
    if(this.nextCharsDisplayRef.current) this.nextCharsDisplayRef.current.resetTimer();
    return;
   }
   this.callChildTestInput(command);
  } else {
   // For other input, just return it to the terminal.
   let wpm = this.handexTerm.handleCharacter(data);

   if (data.charCodeAt(0) === 27) { // escape and navigation characters
    // console.log(
    //  "BufferXY:", this.terminal.buffer.active.cursorX, this.terminal.buffer.active.cursorY,
    //  "lines", this.terminal.buffer.active.viewportY, "chars:", data.split('').map(x => x.charCodeAt(0)));
    if (data.charCodeAt(1) === 91) {
     if (data.charCodeAt(2) === 65 && this.terminal.buffer.active.cursorY < 2) {
      return;
     }
     if (
      data.charCodeAt(2) === 68
      && (
       this.terminal.buffer.active.cursorX < this.promptLength
       && this.terminal.buffer.active.cursorY === 0)
     ) {
      return;
     }
    }
   }

   this.terminal.write(data);
  }
 }

 private setViewPortOpacity(): void {
  const viewPort = document.getElementsByClassName('xterm-viewport')[0] as HTMLDivElement;
  viewPort.style.opacity = "0.5";
 }

 private loadFontSize(): void {
  const fontSize = localStorage.getItem('terminalFontSize');
  if (fontSize) {
   this.currentFontSize = parseInt(fontSize);
   this.terminalElement.style.fontSize = `${this.currentFontSize}px`;
   this.terminal.options.fontSize = this.currentFontSize;
  }
 }

 public toggleVideo(): boolean {
  this.isShowVideo = !this.isShowVideo;
  this.webCam.toggleVideo(this.isShowVideo);
  return this.isShowVideo;
 }

 public getCommandHistory(): HTMLElement[] {
  return this.handexTerm.getCommandHistory();
 }

 private getCurrentCommand(): string {
  const buffer = this.terminal.buffer.active;
  // Assuming the command prompt starts at the top of the terminal (line 0)
  // Adjust the starting line accordingly if your prompt starts elsewhere
  let command = '';
  for (let i = 0; i <= buffer.cursorY; i++) {
   const line = buffer.getLine(i);
   if (line) {
    command += line.translateToString(true);
   }
  }
  return command.substring(command.indexOf(this.promptDelimiter) + 2);
 }


 private loadCommandHistory(): void {
  const commandHistory = this.handexTerm.getCommandHistory();
  this.outputElement.innerHTML = commandHistory.join('');
 }

 private createOutputElement(): HTMLElement {
  const output = document.createElement('div');
  output.id = 'terminal-output';
  output.classList.add('terminal-output');
  // Additional styles and attributes can be set here
  return output;
 }

 private createVideoElement(isVisible: boolean = false): HTMLVideoElement {
  const video = document.createElement('video');
  video.id = 'terminal-video';
  video.hidden = !isVisible;
  // Additional styles and attributes can be set here
  return video;
 }

 prompt(user: string = 'guest', host: string = 'handex.io') {
  const promptText = `\x1b[1;34m${user}@${host} \x1b[0m\x1b[1;32m~${this.promptDelimiter}\x1b[0m `;
  this.promptLength = promptText.length - 21;
  this.terminal.write(promptText);
  // this.promptLength = this.terminal.buffer.active.cursorX;
 }

 // Method to render data to the terminal
 renderOutput(data: string): void {
  this.terminal.write(data);
 }

 // Implement the interface methods
 private addTouchListeners(): void {
  this.terminalElement.addEventListener('touchstart', this.handleTouchStart.bind(this), { passive: false });
  this.terminalElement.addEventListener('touchmove', this.handleTouchMove.bind(this), { passive: false });
  this.terminalElement.addEventListener('touchend', this.handleTouchEnd.bind(this));
 }

 private handleTouchStart(event: TouchEvent): void {
  setTimeout(() => {
   this.terminalElement.focus();
  }, 500)
  if (event.touches.length === 2) {
   event.preventDefault();
   this.lastTouchDistance = this.getDistanceBetweenTouches(event.touches);
  }
 }

 private handleTouchMove(event: TouchEvent): void {
  if (event.touches.length === 2) {
   event.preventDefault();
   const currentDistance = this.getDistanceBetweenTouches(event.touches);
   if (this.lastTouchDistance) {
    const scaleFactor = currentDistance / this.lastTouchDistance;
    this.currentFontSize *= scaleFactor;
    this.terminalElement.style.fontSize = `${this.currentFontSize}px`;
    this.lastTouchDistance = currentDistance;
    const currentFontSize = this.terminal.options.fontSize;
    this.terminal.options.fontSize = this.currentFontSize;
    this.terminal.refresh(0, this.terminal.rows - 1); // Refresh the terminal display
   }
  }
 }

 private handleTouchEnd(event: TouchEvent): void {
  localStorage.setItem('terminalFontSize', `${this.currentFontSize}`);
  this.lastTouchDistance = null;
 }

 private getDistanceBetweenTouches(touches: TouchList): number {
  const touch1 = touches[0];
  const touch2 = touches[1];
  return Math.sqrt(
   Math.pow(touch2.pageX - touch1.pageX, 2) +
   Math.pow(touch2.pageY - touch1.pageY, 2),
  );
 }

 handleNewPhraseSet(phrase: string) {
  this.setState({ isInPhraseMode: true, phrase: phrase });
 }

 render() {
  // Use state and refs in your render method
  return (
   <>
    <NextCharsDisplay
     ref={this.nextCharsDisplayRef}
     onNewPhraseSet={this.handleNewPhraseSet}
    />
   </>
  );
 }
}

Codeium at 3:02 pm, May 13, 2024

The error you're encountering is likely due to the fact that this.setState is being called within the onDataHandler method, which might be getting triggered by some initial setup or command before the component is fully mounted. This could happen, for example, if onDataHandler is called as a result of setting up the Terminal in the constructor.

One possible solution to avoid this problem is to defer the call to this.setState until after the component has mounted. This can be accomplished by using a flag that checks whether the component is mounted. Here's how you could implement this:

First, add a mounted flag to the class:

export class XtermAdapter extends React.Component<any, any> {
  // Existing code...
  
  private _isMounted: boolean = false; // Add this line
  
  // ...
  
  componentDidMount() {
    this._isMounted = true; // Set to true when component is mounted
  }

  componentWillUnmount() {
    this._isMounted = false; // Set to false when component will unmount
  }

  public onDataHandler(data: string): void {
    // Existing onDataHandler code...
    
    if (command === 'phrase') {
      if(this._isMounted) { // Only call setState if component is mounted
        this.setState({ isInPhraseMode: true });
      } else {
        // If the component is not yet mounted, you can't use setState.
        // Instead, you could set a flag and check it in componentDidMount.
        // For example:
        // this._pendingStateChange = { isInPhraseMode: true };
      }
    }
    
    // ...
  }

  componentDidMount() {
    // Existing componentDidMount logic...
    
    if (this._pendingStateChange) { // Check if there is any pending state change
      this.setState({ ...this._pendingStateChange });
      this._pendingStateChange = null; // Reset the pending state change
    }
  }

  // ...
  
  private _pendingStateChange: any = null; // Add this line for pending state changes
}

This approach uses a flag _isMounted to track if the component is mounted. When onDataHandler is called, it checks this flag before calling setState. If the component is not mounted, it sets _pendingStateChange instead. Then, in componentDidMount, it applies any pending state changes.

Please note that using _isMounted flags and deferred state updates is not the typical React pattern and can be error-prone. It's usually better to structure your code so that data is processed in a way that doesn't require state changes before mounting (e.g., via props, context, or during lifecycle events like componentDidMount). However, given the specifics of your use case, where terminal data handling starts very early, this workaround might be necessary.

User at 3:19 pm, May 13, 2024

I am trying your suggestion above, that I call functions on a child component by creating a ref to the child component:

 private nextCharsDisplayRef: React.RefObject<NextCharsDisplay> = React.createRef(); 

But when I call this, nextCharsDisplayRef.current is null:

 callChildTestInput = (testPhrase: string) => {
  if(this.nextCharsDisplayRef.current) this.nextCharsDisplayRef.current.updateDisplay(testPhrase);
 }

Codeium at 3:19 pm, May 13, 2024

The issue where nextCharsDisplayRef.current is null can occur if the NextCharsDisplay component has not been rendered yet or if the ref is not properly attached to the component. Here's a checklist to ensure that your ref is set up correctly:

  1. Check that NextCharsDisplay is a class component: Refs can only be attached to class components or DOM elements, not functional components unless they use React.forwardRef.

  2. Ensure that NextCharsDisplay is rendered: The ref will be null until the component has been mounted in the DOM. Verify that the render method of XtermAdapter is being called and that NextCharsDisplay is part of its output.

  3. Attach the ref in the render method: Make sure you are attaching the ref to NextCharsDisplay correctly in the render method of XtermAdapter.

Here's how you should attach the ref in the render method:

render() {
  // Use state and refs in your render method
  return (
    <>
      <NextCharsDisplay
        ref={this.nextCharsDisplayRef}
        onNewPhraseSet={this.handleNewPhraseSet}
      />
    </>
  );
}
  1. Ref is not supported on function components: If NextCharsDisplay is a functional component, you'll need to use React.forwardRef to forward the ref to a DOM element or another class component inside NextCharsDisplay.

Here's an example of how you can implement forwardRef if NextCharsDisplay is a functional component:

const NextCharsDisplay = React.forwardRef((props, ref) => {
  // Access ref with ref.current
  useImperativeHandle(ref, () => ({
    updateDisplay(testPhrase) {
      // Your update display logic here
    }
  }));

  return (
    // JSX for NextCharsDisplay
  );
});
  1. Timing of the method call: Make sure you are calling callChildTestInput after the component has been mounted. If you're calling it too early (e.g., in the constructor or right after mounting XtermAdapter), the NextCharsDisplay component might not have been rendered and attached the ref yet.

If you've gone through these checks and are still facing issues, please share more context about how and when callChildTestInput is being called, as well as the implementation of NextCharsDisplay (whether it's a class or functional component) so I can provide more precise assistance.

User at 3:56 pm, May 13, 2024

Is it more React appropriate to create a ref to the child component or to use a state change?

What is need for using a state change instead?

User at 3:57 pm, May 13, 2024

Is it more React appropriate to create a ref to the child component or to use a state change? What is need for using a state change instead?

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