pruf

Framework agnostic validation library in JavaScript

Installation

npm i --save pruf

Use

Import validate to validate objects by a set of rules

import { validate, required, between, reporter } from "pruf";

const data = {
  name: "",
  data: { age: 14 },
  zip: 500,
};

const rule = {
  name: {
    required,
  },
  data: {
    age: {
      required,
      over16: (value) => value > 16,
    },
  },
  zip: {
    required: reporter(required, "Please enter ZIP"),
    between: reporter(between(999, 10000), "Invalid ZIP"),
  },
};

const result = validate(rule, data);

the validation results in a new object with valid-keys corresponding to the validations done.

const result = {
  valid: false,
  name: {
    valid: false,
    required: false,
  },
  data: {
    valid: false,
    age: {
      valid: false,
      required: true,
      over16: false,
    },
  },
  zip: {
    valid: false,
    required: { valid: true },
    between: { valid: false, error: "Invalid ZIP" },
  },
};

Validation · validate()

Pruf provides you a simple way to validate data by a set of rules.

With validate(rule, data, options?) you validate an object data by a set of rules provided in a rule object. With an options object you can control some additional behaviour.

Set of rule · rule

The validation follows this set of rules. If a value in the rule object is a function this will be used as the validator for the corresponding data.
The return will have the same structure as the rule.

const rule = {
  name: {
    required,
  },
  data: {
    age: {
      required,
      over16: (value) => value > 16,
    },
  },
  zip: {
    valid: false,
    required: { valid: true },
    between: { valid: false, error: "Invalid ZIP" },
  },
};

Data · data

Any kind of object. Including deeply nested objects.

const data = {
  name: "",
  data: { age: 14 },
  zip: 500,
};

Options · options

Key validKey

string? — default: valid
The name of the key generated during validation.

Key includeKey

string? — default: include The name of the key to detect groups during validation.

Key visitor

object? — default:

{
  isValidator: ({ value }) => typeof value === "function",
  validate: ({ validator, data, parent }) => validator(data, parent),
}

A custom visitor (walker) can be defined to adjust the default behaviour to recognise validators and to validate the corresponding values.

const rule = {
  name: {
    isTruthy: true,
  },
  age: {
    isFalsy: false,
  },
};
const data = {
  name: "Hello",
  age: null,
};

const visitor = {
  isValidator: ({ value }) => value === true || value === false,
  validate: ({ validator, data }) => {
    return validator === false ? !!data === false : !!data === true;
  },
};

const result = validate(rule, data, { visitor });

The visitor detects a validator by the boolean return of a function in the key isValidator. The validation in the key validate can return a boolean or an object. If the return is an object the the key valid must be present (corresponding to validKey) .

const result = {
  valid: true,
  name: {
    valid: true,
    isTruthy: true,
  },
  age: {
    valid: true,
    isFalsy: true,
  },
};

Return value · return

The result of the function returns a new object where each object will have a valid-key with the result of the validation of the values and sub-values. Each validator will leave a key in the object.

const result = {
  valid: false,
  name: {
    valid: false,
    required: false,
  },
  data: {
    valid: false,
    age: {
      valid: false,
      required: true,
      over16: false,
    },
  },
  zip: {
    valid: false,
    required: { valid: true },
    between: { valid: false, error: "Invalid ZIP" },
  },
};

Validators

pruf comes with some often used validation functions.

Helper	Parameters	Description
required	–	Checks if a value is given. required([]) === true, required(0) === true, required(false) === true
between	min, max	Checks if a number is between min and max. Min and max are not included.

Validation messages · reporter

If an error-message on the result object is needed a helper function reporter is provided. The reporter transforms a validator result to a object with the message in an error key and a key valid with the result of the validator.

import { validate, required, between, reporter } from "pruf";

const data = {
  zip: 500,
};

const rule = {
  zip: {
    required: required,
    between: reporter(between(999, 10000), "Invalid ZIP"),
  },
};

const result = validate(rule, data);

const result = {
  zip: {
    valid: false,
    required: true,
    between: { valid: false, error: "Invalid ZIP" },
  },
};

Custom validators

Custom validations can be defined by adding simple functions:

const isPruf = (value) => value === "pruf";

The validation can then be used like all other checks:

const rule = {
  dataYeah: { required, isPruf },
  dataNo: { required, isPruf },
};

The first parameter to the validator is the value to validate. As second parameter there is the parent object.

Grouping

Sometimes it’s useful to have validations grouped. This can be achieved if the key include is set with an array of include paths.

const rule = {
  name: {
    firsName: {
      required,
    },
  },
  age: {
    required,
  },
  person: {
    include: ["name.firsName", "age"], // ← 💫 includes
  },
};

const result = {
  valid: false,
  name: {
    valid: false,
    firsName: {
      valid: true,
      required: true,
    },
  },
  age: {
    valid: false,
    required: false,
  },
  person: {
    valid: false,
    "name.firsName": {
      valid: true,
      required: true,
    },
    age: {
      valid: false,
      required: false,
    },
  },
};

Credits

pruf is inspred by projects like vuelidate, formik and many others.

License & Authors

MIT · Started by signalwerk supported by contributors