javascriptreactjsreact-hooksdynamic-forms

React Dynamic Input form shown Error Some Issues


I am creating Dynamic input fields I am validating some required fields my validated output in the array I try to show error values in input I cause some errors. I tried an some match with an index array but i not working

codeSandbox :https://codesandbox.io/s/floral-bash-lrvkc?file=/src/App.js:0-2399

thanks for Help

import React, { useState } from "react";
import "./styles.css";

function App() {
  const [inputList, setInputList] = useState([{ firstName: "", lastName: "" }]);
  const [formError, setFormError] = useState([]);
  const [isSubmit, setisSubmit] = useState(false);

  // handle input change
  const handleInputChange = (e, index) => {
    const { name, value } = e.target;
    const list = [...inputList];
    list[index][name] = value;
    setInputList(list);
  };

  // handle click event of the Remove button
  const handleRemoveClick = (index) => {
    const list = [...inputList];
    list.splice(index, 1);
    setInputList(list);
  };

  // handle click event of the Add button
  const handleAddClick = () => {
    setInputList([...inputList, { firstName: "", lastName: "" }]);
  };
  const Submit = (e) => {
    e.preventDefault();
    const errorMsg = inputList.map((list, key) => {
      let error = {};
      if (!list.firstName) {
        error.errorfirstName = "FirstName is required";
      } else {
        error.errorfirstName = "";
      }
      if (!list.lastName) {
        error.errorlastName = "LastName is required";
      } else {
        error.errorlastName = "";
      }
      return error;
    });
    console.log(errorMsg);
    setFormError(errorMsg);
  };

  return (
    <div className="App">
      {inputList.map((x, i) => {
        return (
          <div className="box">
            <input
              name="firstName"
              placeholder="Enter First Name"
              value={x.firstName}
              onChange={(e) => handleInputChange(e, i)}
            />
            <input
              className="ml10"
              name="lastName"
              placeholder="Enter Last Name"
              value={x.lastName}
              onChange={(e) => handleInputChange(e, i)}
            />
            <div className="btn-box">
              {inputList.length !== 1 && (
                <button className="mr10" onClick={() => handleRemoveClick(i)}>
                  Remove
                </button>
              )}
              {inputList.length - 1 === i && (
                <button onClick={handleAddClick}>Add</button>
              )}
            </div>
          </div>
        );
      })}
      <button onClick={Submit}>Submit</button>
      <div style={{ marginTop: 20 }}>{JSON.stringify(inputList)}</div>
    </div>
  );
}

export default App;

Solution

  • Please see the below code. I have added some code - see comments marked by // CHANGE HERE

    import React, { useState } from "react";
    import "./styles.css";
    
    function App() {
      const [inputList, setInputList] = useState([{ firstName: "", lastName: "" }]);
      const [formError, setFormError] = useState([]);
      const [isSubmit, setisSubmit] = useState(false);
    
      // handle input change
      const handleInputChange = (e, index) => {
        const { name, value } = e.target;
        const list = [...inputList];
        list[index][name] = value;
        setInputList(list);
      };
    
      // handle click event of the Remove button
      const handleRemoveClick = (index) => {
        const list = [...inputList];
        list.splice(index, 1);
        setInputList(list);
      };
    
      // handle click event of the Add button
      const handleAddClick = () => {
        setInputList([...inputList, { firstName: "", lastName: "" }]);
      };
    
      // CHANGE HERE: a flag to be set when there is an error
      var isError = false;
    
      const Submit = (e) => {
        e.preventDefault();
        const errorMsg = inputList.map((list, key) => {
          let error = {};
          if (!list.firstName) {
            error.errorfirstName = "FirstName is required";
            // CHANGE HERE: set error flag
            isError = true;
          } else {
            error.errorfirstName = "";
          }
          if (!list.lastName) {
            error.errorlastName = "LastName is required";
            // CHANGE HERE: set error flag
            isError = true;
          } else {
            error.errorlastName = "";
          }
          return error;
        });
        console.log(errorMsg);
        setFormError(errorMsg);
        // CHANGE HERE: return false and prevent form submission in case of errors
        if (isError)
          return false;
      };
    
      // CHANGE HERE: added Error function
      const Error = () => {
        return <>
          {formError.map((error, i) => {
            var str = error.errorfirstName + " " + error.errorlastName;
            if (str !== ' ')
              return <p key={i.toString()}> {i} {str}</p>;
            return <></>
          })}
        </>;
      };
    
      return (
        <div className="App">
          {inputList.map((x, i) => {
            return (
              <div className="box">
                <input
                  name="firstName"
                  placeholder="Enter First Name"
                  value={x.firstName}
                  onChange={(e) => handleInputChange(e, i)}
                />
                <input
                  className="ml10"
                  name="lastName"
                  placeholder="Enter Last Name"
                  value={x.lastName}
                  onChange={(e) => handleInputChange(e, i)}
                />
                <div className="btn-box">
                  {inputList.length !== 1 && (
                    <button className="mr10" onClick={() => handleRemoveClick(i)}>
                      Remove
                    </button>
                  )}
                  {inputList.length - 1 === i && (
                    <button onClick={handleAddClick}>Add</button>
                  )}
                </div>
              </div>
            );
          })}
          <button onClick={Submit}>Submit</button>
          // CHANGE HERE: show an error if any
          <Error />
          <div style={{ marginTop: 20 }}>{JSON.stringify(inputList)}</div>
        </div>
      );
    }
    
    export default App;