watsons

JavaScript parameter validation inspired by prop-types.

Requirements

watsons.js requires node.js v6 and above.

Installation

npm install watsons.js

Usage

Normal usage

const watsons = require('watsons.js')
const obj = {
  s: "string value",
  n: 3,
  a: [1, 2, 3, 4],
  e: "female",
  shape: {
    a: 100,
    b: [1, 2, true]
  },
  nullableString: null,
  place: "New York"
}
const checker = {
  s: watsons.string,
  b: watsons.bool,
  n: watsons.number.required,
  a: watsons.arrayOf(
    watsons.number
  ),
  e: watsons.oneOf(["male", "female"]),
  shape: watsons.shape({
    a: watsons.number.required,
    b: watsons.array.required
  }),
  nullableString: watsons.oneOfType([
    watsons.string,
    watsons.null
  ]).required,
  place: watsons.validateWith((v) => v === "New York")
}
watsons.validate(obj, checker) // will not throw
watsons.valid(obj, checker) // returns true

Extending watsons

watsons.addValidator("match", function(s, keyPath, root, regexp) {
  if (s === undefined) return;
  if (!regexp.test(s)) {
    throw new WatsonsError(`String value at keyPath \
'${formatKeyPath(keyPath)}' does not match ${regexp.toString()}.`);
  }
}, true, ["string"]);

const obj = {
  a: "a"
};
const checker = {
  a: watsons.string.match(/a/)
};

watsons.validate(obj, checker); // will not throw

Configuration

By default, watsons checks validator dependencies, it's useful during development process. However, in production environment, it's unnecessary and not efficiency.

watsons.config({checkDeps: false})

Documentation

Watsons is designed to be extensible.

Builtin validators

• shape

the default one for shaped object, works in the way similar to prop-types.

• objectOf

object which values should passing the provided validator. similar to prop-types.

• arrayOf

similar to objectOf but the object being validated should be array.

• instanceOf

object which is instance of provided class. similar to prop-types.

• array

array type.

• bool

boolean type.

• func

function type.

• number

number type.

• object

object type.

• string

string type.

• symbol

symbol type.

• date

date type.

• regexp

regular expression type.

• null

null type.

• required

value is required.

• any

any value, null validator.

• oneOf

enum validator.

• oneOfType

combined validator.

• validateWith

validate with custom function.

• rule

validate with custom message, useful for form data validation.

• rules

validate with rule entries, useful for form data validation.

Extending with new validators

watsons.addvalidator(name, validatorFunc, acceptParams, dependencies)

Parameters:

name: validator name string,

validatorFunc: (value, keyPath, root, params)

acceptParams: whether accepts params or not

dependencies: required chained validators before this validator