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Vue Prop Types definitions
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vue-types

Prop type definitions for Vue.js. Compatible with both Vue 1.x and 2.x

Introduction

vue-types is a collection of configurable prop type definitions for Vue.js components, inspired by React's prop-types.

When to use

While basic prop type definition in Vue is simple and convenient, detailed prop validation can become verbose on complex components. This is the case for vue-types.

Instead of:

export default {
  props: {
    id: {
      type: Number,
      default: 10
    },
    name: {
      type: String,
      required: true
    },
    age: {
      type: Number,
      validator(value) {
        return Number.isInteger(value)
      }
    },
    nationality: String
  },
  methods: {
    // ...
  }
};

You may write:

import VueTypes from 'vue-types';

export default {
  props: {
    id: VueTypes.number.def(10),
    name: VueTypes.string.isRequired,
    age: VueTypes.integer,
    // No need for `default` or `required` key, so keep it simple
    nationality: String
  },
  methods: {
    // ...
  }
}

Installation

NPM package

npm install vue-types --save
# or
yarn add vue-types

CDN delivered <script>

add the following script tags before your code

<script src="https://unpkg.com/vue-types"></script>

Usage with eslint-plugin-vue

When used in a project with eslint-plugin-vue, the linter might report errors related to the vue/require-default-prop rule.

To prevent that error use eslint-plugin-vue-types

Production build

Vue.js does not validate components' props when used in a production build. If you're using a bundler such as Webpack or rollup you can shrink vue-types filesize by around 70% (minified and gzipped) by removing the validation logic while preserving the library's API methods. To achieve that result setup an alias to vue-types/es/shim.js (vue-types/dist/shim.js if you're using CommonJS modules).

Webpack

The following example will shim the module in Webpack by adding an alias field to the configuration when NODE_ENV is set to "production":

// webpack.config.js

return {
  // ... configuration
  resolve: {
    alias: {
      'vue-types': process.env.NODE_ENV === 'production' ? 'vue-types/es/shim.js' : undefined
    }
  }
}

Rollup

The following example will shim the module in rollup using rollup-plugin-alias when NODE_ENV is set to "production":

// rollup.config.js
import alias from 'rollup-plugin-alias';

return {
  // ... configuration
  plugins: [
    process.env.NODE_ENV === 'production' ? alias({
      'vue-types': './node_modules/vue-types/es/shim.js'
    })
  ]
}

Note: If you are using rollup-plugin-node-resolve make sure to place the alias plugin before the resolve plugin.

Documentation

Native Types

Most native types come with:

  • a default value (not available in .any and .symbol).
  • a .def(any) method to reassign the default value for the current prop. The passed-in value will be validated against the type configuration in order to prevent invalid values.
  • a isRequired flag to set the required: true key.
  • a validate(function) method to set a custom validator function (not available in .integer).
const numProp = VueTypes.number
// numProp === { type: Number, default : 0}

const numPropCustom = VueTypes.number.def(10)
// numPropCustom ===  { type: Number, default : 10}

const numPropRequired = VueTypes.number.isRequired
// numPropRequired ===  { type: Number, required : true}

const numPropRequiredCustom = VueTypes.number.def(10).isRequired
// numPropRequiredCustom ===  { type: Number, default: 10, required : true}

const gtTen = (num) => num > 10
const numPropGreaterThanTen = VueTypes.number.validate(gtTen)
// numPropGreaterThanTen ===  { type: Number, validator: (num) => num > 10 }

VueTypes.any

Validates any type of value and has no default value.

VueTypes.array

Validates that a prop is an array primitive.

  • default: an empty array

Note: Vue prop validation requires Array definitions to provide default value as a factory function. VueTypes.array.def() accepts both factory functions and arrays. In the latter case, VueTypes will convert the value to a factory function for you.

VueTypes.bool

Validates boolean props.

  • default: true

VueTypes.func

Validates that a prop is a function.

  • default: an empty function

VueTypes.number

Validates that a prop is a number.

  • default: 0

VueTypes.integer

Validates that a prop is an integer.

  • default: 0

VueTypes.object

Validates that a prop is an object.

  • default: an empty object

Note: Vue prop validation requires Object definitions to provide default value as a factory function. VueTypes.object.def() accepts both factory functions and plain objects. In the latter case, VueTypes will convert the value to a factory function for you.

VueTypes.string

Validates that a prop is a string.

  • default: ''

VueTypes.symbol

VueTypes.symbol

Validates that a prop is a Symbol.

  • default: none

Native Types Configuration

All native types (with the exception of any) come with a sensible default value. In order to modify or disable it you can set the global option VueTypes.sensibleDefaults:

//use vue-types default (this is the "default" value)
VueTypes.sensibleDefaults = true

//disable all sensible defaults.
//Use .def(...) to set one
VueTypes.sensibleDefaults = false

//assign an object in order to specify custom defaults
VueTypes.sensibleDefaults = {
  string: 'mystringdefault'
  //...
}

Under the hood VueTypes.sensibleDefaults is a plain object with just some added magic. That let's you play with it like you'd do with every other object.

For example you can remove some of the default values by leveraging object rest spread or lodash.omit like functions.

// copy every default value but boolean

console.log(VueTypes.bool.default)
// logs true

const { bool, ...newDefaults } = VueTypes.sensibleDefaults

VueTypes.sensibleDefaults = newDefaults
// or VueTypes.sensibleDefaults = _.omit(VueTypes.sensibleDefaults, ['bool'])

console.log(VueTypes.bool.default)
// logs undefined

Custom Types

Custom types are a special kind of types useful to describe complex validation requirements. By design each custom type:

  • doesn't have any sensible default value
  • doesn't have a validate method
  • has a .def() method to assign a default value on the current prop
  • has an isRequired flag to set the required: true key
const oneOfPropDefault = VueTypes.oneOf([0, 1]).def(1)
// oneOfPropDefault.default === 1

const oneOfPropRequired = VueTypes.oneOf([0, 1]).isRequired
// oneOfPropRequired.required ===  true

const oneOfPropRequiredCustom = VueTypes.oneOf([0, 1]).def(1).isRequired
// oneOfPropRequiredCustom.default ===  1
// oneOfPropRequiredCustom.required === true

VueTypes.instanceOf()

class Person {
  // ...
}

export default {
  props: {
    user: VueTypes.instanceOf(Person)
  }
}

Validates that a prop is an instance of a JavaScript constructor. This uses JavaScript's instanceof operator.

VueTypes.oneOf()

Validates that a prop is one of the provided values.

export default {
  props: {
    genre: VueTypes.oneOf(['action', 'thriller'])
  }
}

VueTypes.oneOfType()

Validates that a prop is an object that could be one of many types. Accepts both simple and vue-types types.

export default {
  props: {
    theProp: VueTypes.oneOfType([
      String,
      VueTypes.integer,
      VueTypes.instanceOf(Person)
    ])
  }
}

VueTypes.arrayOf()

Validates that a prop is an array of a certain type.

export default {
  props: {
    theProp: VueTypes.arrayOf(String)
  }
}

//accepts: ['my', 'string']
//rejects: ['my', 1]

VueTypes.objectOf()

Validates that a prop is an object with values of a certain type.

export default {
  props: {
    userData: VueTypes.objectOf(String)
  }
}

//accepts: userData = {name: 'John', surname: 'Doe'}
//rejects: userData = {name: 'John', surname: 'Doe', age: 30}

VueTypes.shape()

Validates that a prop is an object taking on a particular shape. Accepts both simple and vue-types types. You can set shape's properties as required but (obviously) you cannot use .def(). On the other hand you can use def() to set a default value for the shape itself. Like VueTypes.array and VueTypes.object, you can pass to .def() either a factory function returning an object or a plain object.

export default {
  props: {
    userData: VueTypes.shape({
      name: String,
      age: VueTypes.integer,
      id: VueTypes.integer.isRequired
    }).def(() => ({ name: 'John' }))
  }
}

// default value = {name: 'John'}
//accepts: userData = {name: 'John', age: 30, id: 1}
//rejects: userData = {name: 'John', age: 'wrong data', id: 1}
//rejects: userData = {name: 'John', age: 'wrong data'} --> missing required `id` key

By default .shape() won't validate objects with properties not defined in the shape. To allow partial matching use the loose flag:

export default {
  props: {
    userData: VueTypes.shape({
      name: String,
      id: VueTypes.integer.isRequired
    }),
    userDataLoose: VueTypes.shape({
      name: String,
      id: VueTypes.integer.isRequired
    }).loose
  }
}

//accepts: userData = {name: 'John', id: 1}
//rejects: userData = {name: 'John', age: 30, id: 1}
//accepts: userData2 = {name: 'John', age: 30, id: 1} --> loose matching

VueTypes.custom()

Validates prop values against a custom validator function.

function minLength(value) {
    return typeof value === 'string' && value.length >= 6
  }

export default {
  props: {
    theProp: VueTypes.custom(minLength)
  }
}

//accepts: 'string'
//rejects: 'my', 1

Note that the passed-in function name will be used as the custom validator name in warnings.

You can pass a validation error message as second argument as well:

function minLength(value) {
    return typeof value === 'string' && value.length >= 6
  }

export default {
  props: {
    theProp: VueTypes.custom(
      minLength,
      'theProp is not a string or is too short'
    )
  }
}

Extending VueTypes

You can extend VueTypes with your own types via VueTypes.extend({...}). The method accepts an object with every key supported by Vue prop validation objects plus the following custom properties:

  • name: (string, required) The type name. Will be exposed as VueType.
  • validate: (boolean, default: false) If true the type will have a validate method like native types.
  • getter: (boolean, default: false) If true will setup the type as an accessor property (like, for example VueTypes.string) else will setup the type as a configurable method (like, for example VueTypes.arrayOf).

Examples:

// as an accessor type
VueTypes.extend({
  name: 'negative',
  getter: true,
  type: Number,
  validator: (v) => v < 0
})

const negativeProp = VueTypes.negative

// as a configurable method
VueTypes.extend({
  name: 'negativeFn',
  type: Number,
  validator: (v) => v < 0
})

const negativeProp2 = VueTypes.negativeFn() // <-- we need to call it

Note that if getter is set to false, arguments passed to the type will be passed to the validator method together with the prop value:

VueTypes.extend({
  name: 'maxLength',
  // getter: false, this is the default
  type: String,
  validator: (max, v) => v.length <= max
})

const maxLengthType = VueTypes.maxLength(2)

maxLengthType.validator('ab') // true
maxLengthType.validator('abcd') // false

Typescript

When used in a TypeScript project, types added via .extend() might fail type checking. In order to instruct TypeScript about your custom types you can use the following pattern:

// propTypes.ts

// import
// - VueTypes library
// - validation object interface (VueTypeDef)
// - the default VueType interface (VueTypesInterface)
import VueTypes, { VueTypeDef, VueTypesInterface } from 'vue-types'

interface ProjectTypes extends VueTypesInterface {
  //VueTypeDef accepts the prop expected type as argument
  maxLength(max: number): VueTypeDef<string>
}

VueTypes.extend({
  name: 'maxLength',
  type: String,
  validator: (max: number, v: string) => v.length <= max
})

export default VueTypes as ProjectTypes

Then import the newly created propTypes.ts instead of vue-types:

<!-- MyComponent.vue -->
<template>
<!-- template here -->
</template>
<script lang="ts">
import Vue from "vue";
import VueTypes from "./prop-types";

export default Vue.extend({
  name: "MyComponent",
  props: {
    msg: VueTypes.maxLength(2)
  }
});
</script>

Utilities

vue-types exposes some utility functions on the .utils property:

VueTypes.utils.validate(value, type)

Checks a value against a type definition

VueTypes.utils.validate('John', VueTypes.string) //true

VueTypes.utils.validate('John', { type: String }) //true

Note that this utility won't check for isRequired flag, but will execute any custom validator function is provided.

const isJohn = {
  type: String,
  validator(value) {
    return value.length === 'John'
  }
}

VueTypes.utils.validate('John', isJohn) //true
VueTypes.utils.validate('Jane', isJohn) //false

VueTypes.utils.toType(name, obj)

Will convert a plain object to a VueTypes' type object with .def() and isRequired modifiers:

const password = {
  type: String,
  validator(value) {
    //very raw!
    return value.length > 10
  }
}

const passwordType = VueTypes.utils.toType('password', password)

export default {
  props: {
    password: passwordType.isRequired
  }
}

License

MIT

Copyright (c) 2018 Marco Solazzi

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