js-props-validator

JavaScript object properties validation. See below or src/_tests_/main-test.js for examples.

Getting Started

Install js-props-validator as NPM dependency.

npm install --save js-props-validator

Example

import Props from 'js-props';
 
const validator = Props.object({
    name: Props.string(),
    age: Props.number(),
    phone: Props.string().isOptional(),
    country: Props.oneOf([ 'Austria', 'Germany', 'Switzerland' ]).withDefault('Germany')
  });
 
validator.validate({
    name: 'Egon',
    age: 12
  });
// => true
 
validator.validate({
    name: 'Egon'
  });
// => Will throw exception due to missing age
 
validator.validateValue({
    name: 'Egon',
    age: 'twelve'
  });
// => false due to wrong type for age
 
validator.valueOrDefault({
    name: 'Egon',
  });
// => { name: 'Egon', country: 'Germany' }

Types

Any

Props.any([ ofType: Function | Array [, isOptional: boolean = false [, defaultValue: Any ]]])

Checks for any type. If ofType is a function it will be used to validate the value. E.g.:

const validator = Props.any((value) => value > 10);
validator.validateValue(13) === true;
validator.validateValue(9) === false;

If ofType is an array of Type the value will be checked if it is one of the given types. E.g.:

const validator = Props.any([ Props.number(), Props.string() ]);
validator.validateValue(12) === true;
validator.validateValue(twelve) === true;
validator.validateValue([ 12 ]) === false;

Array

Props.array([ ofType: Type [, isOptional: boolean = false [, defaultValue: Array ]]])

Checks for arrays. ofType can be defined as Type. E.g.:

const validator = Props.array(Props.string());
validator.validateValue([ "a", "b", "c" ]) === true;
validator.validateValue([ 1, 2, 3 ]) === false;

Boolean

Props.bool([ isOptional: boolean = false [, defaultValue: boolean ]])

Checks for boolean.

Enumeration

Props.oneOf(values: Array [, isOptional: boolean = false [, defaultValue: Any ]])

Checks for a set of defined values. E.g.:

const validator = Props.oneOf([ 1, 'A', 2 ]);
validator.validateValue(1) === true;
validator.validateValue('B') === false;

Function

Props.func([ isOptional: boolean = false [, defaultValue: Function ]])

Checks for functions.

Number

Props.number([ isOptional: boolean = false [, defaultValue: Number ]])

Checks for numbers.

Object

Props.object(ofType: Object | Type [, isOptional: boolean = false [, defaultValue: Number ]])

ofType can be a predefined object structure. E.g.:

const validator = Props.object({
    name: Props.string(),
    age: Props.number(),
    phone: Props.string().isOptional(),
    country: Props.oneOf([ 'Austria', 'Germany', 'Switzerland' ]).withDefault('Germany')
  });
 
validator.validate({
    name: 'Egon',
    age: 12
  }) === true;

If ofType is a type, the validator checks if every property of the object meets the type's validations. E.g.:

const validator = Props.object(Props.object({
    label: Props.string(),
    value: Props.any([ Props.number(), Props.string() ])
  }));
 
validator.validateValue({
    id: {
      label: "#",
      value: 0
    },
    name: {
      label: "Name",
      value: "Egon"
    }
  }) === true;
 
validator.validateValue({
    id: {
      value: 0
    },
    name: {
      label: "Name",
      value: "Egon"
    }
  }) === false;

String

Props.string([ isOptional: boolean = false [, defaultValue: String ]])

Checks for strings.

Type methods

Every type supports the following listed methods.

isOptional()

The validation will return true if value is not set.

const validator = Props.number().isOptional(); // alternative to: Props.number(true);
validator.validateValue(1) === true;
validator.validateValue(undefined) === true;
validator.validateValue("one") === false;

withDefault()

The validation will return a default value when calling valueOrDefault on a undefined value. Note: isOptional will be automatically set to true when calling withDefault.

const validator = Props.number().withDefault(42); // alternative to: Props.number(true);
validator.validateValue(1) === true;
validator.validateValue(undefined) === true;
validator.validateValue("one") === false;
 
validator.valueOrDefault(1) === 1;
validator.valueOrDefault(undefined) === 42;

validate(value: Any [, valueName: String])

The Method will validate the value, if the validation fails an error will be thrown. valueName is used within the error message if set.

const validator = Props.object({
    name: Props.string(),
    age: Props.number(),
    phone: Props.string().isOptional(),
    country: Props.oneOf([ 'Austria', 'Germany', 'Switzerland' ]).withDefault('Germany')
  });
 
validator.validate({
    name: 'Egon'
  });
// => Will throw exception due to missing age

validateValue(value: Any [, valueName: String])

Like validate but it will log an warning instead of throwing an error. Returns true if validation was successful, otherwise false.

valueOrDefault(value: Any)

Returns value or the default value when set and value === undefined. See example of withDefault.