Ability to enter tab characters in a TextField?

Question

I have a MUI TextField that is defined as multi-line. My goal is to enter JSON text. I found that when I pressed the tab key, my component lost focus and focus was given to the next component on screen. What I desire is to have the tab value (\\t) entered into the string text. Is there a recipe to disable the tab key as a navigation tool?

Answer 1

By default, if you press Tab in the input field, the browser will switch focus to the next element. To override that behavior, you can listen to the keydown event and call e.preventDefault() , then add some code to insert the tab character at the cursor position. Below is the implementation. Note that because you are tampering with the input value , the undo feature doesn't work anymore:

<TextField
  multiline
  onKeyDown={(e) => {
    const { value } = e.target;

    if (e.key === 'Tab') {
      e.preventDefault();

      const cursorPosition = e.target.selectionStart;
      const cursorEndPosition = e.target.selectionEnd;
      const tab = '\t';

      e.target.value =
        value.substring(0, cursorPosition) +
        tab +
        value.substring(cursorEndPosition);

      // if you modify the value programmatically, the cursor is moved
      // to the end of the value, we need to reset it to the correct
      // position again
      e.target.selectionStart = cursorPosition + 1;
      e.target.selectionEnd = cursorPosition + 1;
    }
  }}
/>

Live Demo