Valivar

Mostly derived from eivindfjeldstad/validate; Valivar provides dynamic schemas for modern javascript and typescript validation and sanitization. In Valivar you can use catch-all keys $ and * to define any array or object respectively, letting you define a single schema that can apply consistent rules for growing and changing datasets.


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Install

Node.js or Browser

npm install valivar

Deno

import valivar from "https://deno.land/x/valivar/mod.ts"

Import in HTML

<script type="text/javascript" src="dist/valivar.js"></script>

From CDN

<script type="text/javascript" src="https://unpkg.com/valivar"></script>

Examples

For a full list see the examples directory (coming)

Experiment yourself

CodePen (coming) JSFiddle (coming)

Reademe rewrite in progress...

Usage

Define a schema and call .validate() with the object you want to validate. The .validate() function returns an array of validation errors.

import Schema from 'validate'

const user = new Schema({
  username: {
    type: String,
    required: true,
    length: { min: 3, max: 32 }
  },
  pets: [{
    name: {
      type: String
      required: true
    },
    animal: {
      type: String
      enum: ['cat', 'dog', 'cow']
    }
  }],
  address: {
    street: {
      type: String,
      required: true
    },
    city: {
      type: String,
      required: true
    }
    zip: {
      type: String,
      match: /^[0-9]+$/,
      required: true
    }
  }
})

const errors = user.validate(obj)

Each error has a .path, describing the full path of the property that failed validation, and a .message describing the error.

errors[0].path //=> 'address.street'
errors[0].message //=> 'address.street is required.'

Custom error messages

You can override the default error messages by passing an object to Schema#message().

const post = new Schema({
  title: { required: true }
})

post.message({
  required: (path) => `${path} can not be empty.`
})

const [error] = post.validate({})
assert(error.message = 'title can not be empty.')

It is also possible to define messages for individual properties:

const post = new Schema({
  title: {
    required: true,
    message: 'Title is required.'
  }
})

And for individual validators:

const post = new Schema({
  title: {
    type: String,
    required: true,
    message: {
      type: 'Title must be a string.',
      required: 'Title is required.'
    }
  }
})

Nesting

Objects and arrays can be nested as deep as you want:

const event = new Schema({
  title: {
    type: String,
    required: true
  },
  participants: [{
    name: String,
    email: {
      type: String,
      required: true
    },
    things: [{
      name: String,
      amount: Number
    }]
  }]
})

Arrays can be defined implicitly, like in the above example, or explicitly:

const post = new Schema({
  keywords: {
    type: Array,
    each: { type: String }
  }
})

Array elements can also be defined individually:

const user = new Schema({
  something: {
    type: Array,
    elements: [
      { type: Number },
      { type: String }
    ]
  }
})

Nesting also works with schemas:

const user = new Schema({
  name: {
    type: String,
    required: true
  },
  email: {
    type: String,
    required: true
  }
})

const post = new Schema({
  title: {
    type: String,
    required: true
  },
  content: {
    type: String,
    required: true
  },
  author: user
})

If you think it should work, it probably works.

Naming conflicts

Validate will naively assume that a nested object where all property names are validators is not a nested object.

const schema = new Schema({
  pet: {
    type: {
      required: true,
      type: String,
      enum: ['cat', 'dog']
    }
  }
});

In this example, the pet.type property will be interpreted as a type rule, and the validations will not work as intended. To work around this we could use the slightly more verbose properties rule:

const schema = new Schema({
  pet: {
    properties: {
      type: {
        required: true,
        type: String,
        enum: ['cat', 'dog']
      }
    }
  }
});

In this case the type property of pets.properties will be interpreted as a nested property, and the validations will work as intended.

Custom validators

Custom validators can be defined by passing an object with named validators to .use:

const hexColor = val => /^#[0-9a-fA-F]$/.test(val)

const car = new Schema({
  color: {
    type: String,
    use: { hexColor }
  }
})

Define a custom error message for the validator:

car.message({
  hexColor: path => `${path} must be a valid color.`
})

Custom types

Pass a constructor to .type to validate against a custom type:

class Car {}

const user = new Schema({
  car: { type: Car }
})

Chainable API

If you want to avoid constructing large objects, you can add paths to a schema by using the chainable API:

const user = new Schema()

user
  .path('username').type(String).required()
  .path('address.zip').type(String).required()

Array elements can be defined by using $ as a placeholder for indices:

const user = new Schema()
user.path('pets.$').type(String)

This is equivalent to writing

const user = new Schema({ pets: [{ type: String }]})

Typecasting

Values can be automatically typecast before validation. To enable typecasting, pass an options object to the Schema constructor with typecast set to true.

const user = new Schema(definition, { typecast: true })

You can override this setting by passing an option to .validate().

user.validate(obj, { typecast: false })

To typecast custom types, you can register a typecaster:

class Car {}

const user = new Schema({
  car: { type: Car }
})

user.typecaster({
  Car: (val) => new Car(val)
})

Property stripping

By default, all values not defined in the schema will be stripped from the object. Set .strip = false on the options object to disable this behavior. This will likely be changed in a future version.

Strict mode

When strict mode is enabled, properties that are not defined in the schema will trigger a validation error. Set .strict = true on the options object to enable strict mode.

API

Table of Contents

set

Set given path

Parameters

Returns Object

get

Get given path

Parameters

Returns Mixed

delete

Delete given path

Parameters

Returns Mixed

Property

A property instance gets returned whenever you call schema.path(). Properties are also created internally when an object is passed to the Schema constructor.

Parameters

  • name String the name of the property
  • schema Schema parent schema

message

Registers messages.

Parameters
Examples
prop.message('something is wrong')
prop.message({ required: 'thing is required.' })

Returns Property

schema

Mount given schema on current path.

Parameters
  • schema Schema the schema to mount
Examples
const user = new Schema({ email: String })
prop.schema(user)

Returns Property

use

Validate using named functions from the given object. Error messages can be defined by providing an object with named error messages/generators to schema.message()

The message generator receives the value being validated, the object it belongs to and any additional arguments.

Parameters
  • fns Object object with named validation functions to call
Examples
const schema = new Schema()
const prop = schema.path('some.path')

schema.message({
  binary: (path, ctx) => `${path} must be binary.`,
  bits: (path, ctx, bits) => `${path} must be ${bits}-bit`
})

prop.use({
  binary: (val, ctx) => /^[01]+$/i.test(val),
  bits: [(val, ctx, bits) => val.length == bits, 32]
})

Returns Property

required

Registers a validator that checks for presence.

Parameters
  • bool Boolean? true if required, false otherwise (optional, default true)
Examples
prop.required()

Returns Property

type

Registers a validator that checks if a value is of a given type

Parameters
Examples
prop.type(String)
prop.type('string')

Returns Property

string

Convenience method for setting type to String

Examples
prop.string()

Returns Property

number

Convenience method for setting type to Number

Examples
prop.number()

Returns Property

array

Convenience method for setting type to Array

Examples
prop.array()

Returns Property

object

Convenience method for setting type to Object

Examples
prop.object()

Returns Property

date

Convenience method for setting type to Date

Examples
prop.date()

Returns Property

length

Registers a validator that checks length.

Parameters
  • rules (Object | Number) object with .min and .max properties or a number
    • rules.min Number minimum length
    • rules.max Number maximum length
Examples
prop.length({ min: 8, max: 255 })
prop.length(10)

Returns Property

size

Registers a validator that checks size.

Parameters
  • rules (Object | Number) object with .min and .max properties or a number
    • rules.min Number minimum size
    • rules.max Number maximum size
Examples
prop.size({ min: 8, max: 255 })
prop.size(10)

Returns Property

enum

Registers a validator for enums.

Parameters
  • enums
  • rules Array allowed values
Examples
prop.enum(['cat', 'dog'])

Returns Property

match

Registers a validator that checks if a value matches given regexp.

Parameters
  • regexp RegExp regular expression to match
Examples
prop.match(/some\sregular\sexpression/)

Returns Property

each

Registers a validator that checks each value in an array against given rules.

Parameters
Examples
prop.each({ type: String })
prop.each([{ type: Number }])
prop.each({ things: [{ type: String }]})
prop.each(schema)

Returns Property

elements

Registers paths for array elements on the parent schema, with given array of rules.

Parameters
  • arr Array array of rules to use
Examples
prop.elements([{ type: String }, { type: Number }])

Returns Property

properties

Registers all properties from the given object as nested properties

Parameters
  • props Object properties with rules
Examples
prop.properties({
  name: String,
  email: String
})

Returns Property

path

Proxy method for schema path. Makes chaining properties together easier.

Parameters
  • args ...any
Examples
schema
  .path('name').type(String).required()
  .path('email').type(String).required()

typecast

Typecast given value

Parameters
  • value Mixed value to typecast
Examples
prop.type(String)
prop.typecast(123) // => '123'

Returns Mixed

validate

Validate given value

Parameters
  • value Mixed value to validate
  • ctx Object the object containing the value
  • path String? path of the value being validated (optional, default this.name)
Examples
prop.type(Number)
assert(prop.validate(2) == null)
assert(prop.validate('hello world') instanceof Error)

Returns ValidationError

Schema

A Schema defines the structure that objects should be validated against.

Parameters

  • obj Object? schema definition (optional, default {})
  • opts Object? options (optional, default {})
    • opts.typecast Boolean typecast values before validation (optional, default false)
    • opts.strip Boolean strip properties not defined in the schema (optional, default true)
    • opts.strict Boolean validation fails when object contains properties not defined in the schema (optional, default false)

Examples

const post = new Schema({
  title: {
    type: String,
    required: true,
    length: { min: 1, max: 255 }
  },
  content: {
    type: String,
    required: true
  },
  published: {
    type: Date,
    required: true
  },
  keywords: [{ type: String }]
})
const author = new Schema({
  name: {
    type: String,
    required: true
  },
  email: {
    type: String,
    required: true
  },
  posts: [post]
})

path

Create or update path with given rules.

Parameters
Examples
const schema = new Schema()
schema.path('name.first', { type: String })
schema.path('name.last').type(String).required()

Returns Property

validate

Validate given obj.

Parameters
  • obj Object the object to validate
  • opts Object? options, see Schema (optional, default {})
Examples
const schema = new Schema({ name: { required: true }})
const errors = schema.validate({})
assert(errors.length == 1)
assert(errors[0].message == 'name is required')
assert(errors[0].path == 'name')

Returns Array

assert

Assert that given obj is valid.

Parameters
Examples
const schema = new Schema({ name: String })
schema.assert({ name: 1 }) // Throws an error

message

Override default error messages.

Parameters
  • name (String | Object) name of the validator or an object with name-message pairs
  • message (String | Function)? the message or message generator to use
Examples
const hex = (val) => /^0x[0-9a-f]+$/.test(val)
schema.path('some.path').use({ hex })
schema.message('hex', path => `${path} must be hexadecimal`)
schema.message({ hex: path => `${path} must be hexadecimal` })

Returns Schema

validator

Override default validators.

Parameters
  • name (String | Object) name of the validator or an object with name-function pairs
  • fn Function? the function to use
Examples
schema.validator('required', val => val != null)
schema.validator({ required: val => val != null })

Returns Schema

typecaster

Override default typecasters.

Parameters
  • name (String | Object) name of the validator or an object with name-function pairs
  • fn Function? the function to use
Examples
schema.typecaster('SomeClass', val => new SomeClass(val))
schema.typecaster({ SomeClass: val => new SomeClass(val) })

Returns Schema

typecast

Cast given val to type

Parameters

string

Cast val to String

Parameters
  • val Mixed

number

Cast val to Number

Parameters
  • val Mixed

date

Cast val to aDate

Parameters
  • val Mixed

array

Cast val to Array

Parameters
  • val Mixed

boolean

Cast val to Boolean

Parameters
  • val Mixed

object

Cast val to Object

Parameters
  • val Mixed

Licence

MIT