Reactjs TextField helperText

Question

how can I synchronize error validation with the character limit without affecting its functions, please see this https://codesandbox.io/s/nostalgic-mestorf-47jsvk?file=/src/App.js

  const [formError, setFormError] = useState(false);
  const CHARACTER_LIMIT = 1000;
  const [getString, setString]= useState({
    value: "",
    length: 0
  })


const onHandleChangeInput = (field, value) => {
  setString({value: value, length: value.length})
}
  const onHandleInputValidation = (field, value) => {
    try {
      Joi.assert(value, _.get(VALIDATION_SCHEMA, field));
      setFormError(_.omit(formError, field));
      return { error: false, valid: true };
    } catch (err) {
      return { error: err.message, valid: false };
    }
  };
     onHandleChangeInput('name', value)}
      error={Boolean(formError.name)}
      helperText={{formError.name}, `${getString.length}/${CHARACTER_LIMIT}`}
    />

what i want is just like this

user_8510405 · Answer

Your onChange handler gets the event. You need to get the value out of it.

Update the onHandleChangeInput like below.

const onHandleChangeInput = (field, event) => {
    const { value } = event.target;
    setString({ value: value, length: value.length });
    onHandleInputValidation(field, value);
};

name the parameter as event instead of value to be clear.

onChange={(event) => onHandleChangeInput("name", event)}

Use a ternary to show error message or helperText.

      helperText={
        Boolean(formError.name)
          ? formError.name
          : `${getString.length}/${CHARACTER_LIMIT}`
      }

user_17497509 · Answer

import React, { useState } from "react";
import { TextField } from "@mui/material";
import "./styles.css";

export default function App() {
  const CHARACTER_LIMIT = 1000;
  const [getString, setString] = useState({
    value: "",
    length: 0
  });
  const onHandleChangeInput = (field, value) => {
    const { value: inputValue } = value.target;
    setString({ value: inputValue, length: inputValue.length });
  };
  return (
     onHandleChangeInput("name", e)}
      error={Boolean(getString.length === CHARACTER_LIMIT)}
      helperText={`${getString.length}/${CHARACTER_LIMIT}`}
    />
  );
}

you are not using value from onChange as you were sending event then I extracted that value for you. Take a look

user_11129751 · Answer

You cannot exceed the charachter limit as long as you have not removed inputProps={{ maxLength: CHARACTER_LIMIT }}, after that you could use FormHelperText component and pass two messages as follows:


  {formError.name}
  {`${getString.length}/${CHARACTER_LIMIT}`

Reactjs TextField helperText

3 Answers