Use-validations NPM

use validations

use validations provides a custom hook to do validations in React in a simple and lightweight way, without changing your components or the global state of your application.

Pretty simple validator example,

import useValidations, { isRequired } from "use-validations";

function App()  {
  const { handleInputChange, data, errors } = useValidations<{ name: string }>({
    defaultData: { name: "" },
    validators: { name: isRequired }
  });

  return (
    <div>
      <label htmlFor="user-name">Username</label>

      <input
        id="user-name"
        type="text"
        onChange={handleInputChange("name")}
        value={data.name}
      />

      {errors.name && <small>{errors.name}</small>}
    </div>
  );
}

export default App;

the validator function receives a string with the value to validate and stores in the errors object, null if the value to validate is valid or a string with the description of the validation error.

Example of a custom validator with more than one validation:

import useValidations from "use-validations";
import differenceInCalendarDays from "date-fns/differenceInCalendarDays";

const customValidator = (date: string) => {
  // get the difference in days between the selected date and today.
  const diffDays = differenceInCalendarDays(new Date(date), new Date());

  // if the difference is less than or equal to -1, it is today or before today.
  if (diffDays <= -1) {
    return "the date should be higher than today.";
  }

  // if the difference is greater than or equal to 3, it is 3 days or more in the future.
  if (diffDays >= 3) {
    return "the date should not be more than 3 days after the current date.";
  }

  return null;
};

function App()  {
  const { handleInputChange, data, errors } = useValidations<{
    scheduleDate: string;
  }>({
    defaultData: { scheduleDate: "" },
    validators: { scheduleDate: customValidator },
  });

  return (
    <div>
      <label htmlFor="schedule-date">Schedule Date</label>

      <input
        id="schedule-date"
        type="date"
        onChange={handleInputChange("scheduleDate")}
        value={data.scheduleDate}
      />

      {errors.scheduleDate && <small>{errors.scheduleDate}</small>}
    </div>
  );
}

export default App;

Parameters.

Key	Value
defaultData	Object with the field name as key and value as value :).
validators	Object with the field name as key and validator function as value.

Return values.

Key	Value
data	Object with the field name as key and a validating function as value.
errors	Object with the field name as key and string error or null as value.
emptyForm	Boolean value that does what it promises.
handleInputChange	Function to handle data changes.
hasErrors	Boolean value that does what it promises.
doValidate	Function that runs all validations, and returns a boolean true if no validation gives an error and false otherwise.
resetData	Function to reset the data to default values.