Repository: freeCodeCamp/freeCodeCamp
File: client/src/components/formHelpers/form-fields.tsx (TypeScript)

Code before:
      if (isSourceCodeLinkRequired) {
        validators.push(sourceCodeLinkExistsValidator);
      }
      validators.push(sourceCodeLinkPublicValidator);
    }
    if (!isLocalLinkAllowed) {
      validators.push(localhostValidator);
    }
    const validationWarning = composeValidators(...validators)(value);
    const message: string = (error ||
      validationError ||
      validationWarning) as string;
    return message ? (
      <HelpBlock id={`${name}-message`}>
        <Alert variant={error || validationError ? 'danger' : 'info'}>
          {message}
        </Alert>
      </HelpBlock>
    ) : null;
  };
  return (
    <>
      {formFields
        .filter(formField => !ignored.includes(formField.name))
        .map(({ name, label }) => (
          <Field key={`${name}-field`} name={name}>
            {({ input: { value, onChange }, meta: { pristine, error } }) => {
              const placeholder =
                name in placeholders ? placeholders[name] : '';
              const isURL = types[name] === 'url';
              return (
                <FormGroup key={name}>
                  <ControlLabel
                    htmlFor={name}
                    data-playwright-test-label={`${name}-control-label`}
                  >
                    {label}
                  </ControlLabel>
                  <FormControl
                    id={name}
                    name={name}
                    onChange={onChange}
                    placeholder={placeholder}
                    required={required.includes(name)}
                    rows={4}
                    type={types[name] || 'text'}
                    value={value as string}
                    aria-describedby={`${name}-message`}
                    data-playwright-test-label={`${name}-form-control`}
                  />
                  {nullOrWarning(

Review comment (suggestion):
`value` is not always a string.

If an initial value isn't provided, `value` will be `undefined` until the user interacts with the field. So the value type should be set to:

```suggestion
          <Field<string | undefined> key={`${name}-field`} name={name}>
```

Then, we remove the `value as string` type cast. And update `nullOrWarning` to take `value: string | undefined` instead.

Code after:
      if (isSourceCodeLinkRequired) {
        validators.push(sourceCodeLinkExistsValidator);
      }
      validators.push(sourceCodeLinkPublicValidator);
    }
    if (!isLocalLinkAllowed) {
      validators.push(localhostValidator);
    }
    const validationWarning = composeValidators(...validators)(value);
    const message: string = (error ||
      validationError ||
      validationWarning) as string;
    return message ? (
      <HelpBlock id={`${name}-message`}>
        <Alert variant={error || validationError ? 'danger' : 'info'}>
          {message}
        </Alert>
      </HelpBlock>
    ) : null;
  };
  return (
    <>
      {formFields
        .filter(formField => !ignored.includes(formField.name))
        .map(({ name, label }) => (
          <Field<string | undefined> key={`${name}-field`} name={name}>
            {({ input: { value, onChange }, meta: { pristine, error } }) => {
              const placeholder =
                name in placeholders ? placeholders[name] : '';
              const isURL = types[name] === 'url';
              return (
                <FormGroup key={name}>
                  <ControlLabel
                    htmlFor={name}
                    data-playwright-test-label={`${name}-control-label`}
                  >
                    {label}
                  </ControlLabel>
                  <FormControl
                    id={name}
                    name={name}
                    onChange={onChange}
                    placeholder={placeholder}
                    required={required.includes(name)}
                    rows={4}
                    type={types[name] || 'text'}
                    value={value as string}
                    aria-describedby={`${name}-message`}
                    data-playwright-test-label={`${name}-form-control`}
                  />
                  {nullOrWarning(