Validee

An object validation library with minimal magic.

Installation

npm install validee

Usage

import { validee, ValideeError, ValideeFn } from 'validee'

// `value` is typed as `string`.
// Validation functions can be synchronous or asynchronous.
const trimInput: ValideeFn<string> = async (value) => {
  // 1. Create an array of errors.
  const errors: string[] = []

  // 2. Perform any validation logic.
  // if (value.length > 10) { errors.push('Must not be longer than 10 characters.') }

  // 3. Return the new value and the errors.
  return {
    value: value.trim(),
    errors,
  }
}

// Define a schema, where the functions follow the same structure as above.
const schema = {
  email: [trimInput, validateEmail],
  username: [trimInput, validateUsername],
  password: [validatePassword],
  some: {
    nested: {
      property: [trimInput], // There is no maximum depth for your data.
    },
  },
}

// Example incoming data.
const badData = {
  email: ' hello@example.com ', // `trimInput` will remove the spaces.
  username: 'hello ', // `trimInput` will remove the space.
  password: 'hello', // `validatePassword` will possibly throw an error here.
  some: {
    nested: {
      property: ' hello', // `trimInput` will remove the space.
    },
  },
}

try {
  // If validation passes, `goodData` is the final version of the data.
  // In this case, `trimInput` will mutate `email` and `username`.
  const goodData = await validee(schema, badData)
} catch (error) {
  // Handle any errors.
  if (error instanceof ValideeError) {
    console.log(error.errors) // => { "password": ["Please choose a better password."] }
  }
}