checktypes-js

checktypes-js is a package to help you check the types of a passed variable. It also allows you to check types of an object using an object scheme or an Array and types of elements within the Array. This package also has typescript support.

Installation

$ npm install checktypes-js --save

Introduction

Sections

1. Installation
2. Usage
   • Objects
     • simple object no properties type check
     • with defined required properties
     • with all required properties
   • Arrays
     • simple array type checking
     • with element type checking
   • Strings
   • Numbers
   • Booleans
   • Symbols
3. Helper functions
   • getVal
   • setVal
   • getType
   • typeToString
   • stringToType
   • propsFromString
4. Contributing
5. License
6. Support

Typescript Support

Use import { CheckTypesError } from 'checktype-js for typings of the error objects. Use the package with maximum type checking advatage.. transpile time and run time type checking. What else could you ask for?

Simple Example

const checkTypes = require('checktypes-js')

const aNumber = 33

const [error, numberPassed] = checkTypes(aNumber, Number)

if(error)
   console.log(error)
else
   // do stuff eith numberPassed

Callback or return style usage

const checkTypes = require('checktypes-js')

/*  Callback function style  */
checkTypes(item: String|Number|Boolean|Symbol|Array|Object,
           type: String|Number|Boolean|Symbol|Array|Object,
   function(error, passedItem){
      if(error){
        // handle error
      } else {
        // do stuff with passedItem
      }
})

// OR

/*  Return value style  */
const [error, passedItem] = checkTypes(item: String|Number|Boolean|Symbol|Array|Object,
                                       type: String|Number|Boolean|Symbol|Array|Object)
if(error){
   // handle error
} else {
   // do stuff with passedItem
}

Usage

Object with Scheme type checking

You can define a scheme with types and can be nested with other Objects or Arrays.

const checkTypes = require("checktypes-js")

const personObject = {
  name: "Shelby",
  age: 32,
  isMarried: true,
  children: [{ name: "Hannah", age: 3 }, { name: "Billy", age: 6 }],
  address: {
    street: {
      number: "123", // <-- ERROR! String instead of Number
      name: "Main st."
    },
    city: "Boston",
    state: "MA",
    country: "USA"
  },
  comments: ["is very nice.", "has a good head on her shoulders"]
}

const personScheme = {
  name: String,
  age: Number,
  isMarried: Boolean,
  children: [{ name: String, age: Number }],
  address: {
    street: {
      number: Number,
      name: String
    },
    city: String,
    state: String,
    country: String
  },
  comments: [String]
}

checkTypes(personObject, personScheme, function(errors, passedObject) {
  if (errors) {
    console.log(errors)
    /*
      [ { propertyName: 'address.street.number',
          expectedType: 'Number',
          recievedType: 'String',
          required: false } ]
    */

    // handle errors...
  } else {
    // do stuff with passedObject...
  }
})

Simple Object with no properties's type checked

const checkTypes = require('checktypes-js')

const objectToCheck = {
   username: 'hannah1010',
   password: 'securePass!',
   comments: ['Hey beautiful', 'You\'re a great human being!']
}

checkTypes(objectToCheck, Object, (errors, passedObject) => {     // or an pass {} instead of Object
   if(errors) {
      // handle any errors
   } else {
      // do stuff with passedObject
})

Required properties in scheme:

You can also specify required fields using $required : [{String name(s) of properties}]

const checkTypes = require('checktypes-js')

const scheme = {
   username: String,
   password: String,
   rememberMe: Boolean,
   $required: ['username', 'password', 'rememberMe']
}

const objectToCheck = {
   username: 'hannah1010',
   password: 'securePass!',    // ERROR! missing 'rememberMe' property
}

checkTypes(objectToCheck, scheme, (errors, passedObject) => {
   if(errors) {
      console.log(errors)
   /*
      [ { propertyName: 'rememberMe',
          expectedType: 'Boolean',
          recievedType: 'None',
          required: true } ]
   */

   } else {
      // do stuff with passedObject
})

Require all properties in scheme:

You also have the ability to specify all scheme properties as required. Import $required from package.

const checkTypes = require('checktypes-js')
const { $required } = checkTypes

const scheme = {
   username: String,
   password: String,
   rememberMe: Boolean,
   $required               // just pass $required
}

const objectToCheck = {
   password: 'securePass!',
   rememberMe: false       // ERROR! missing 'username' property
}

checkTypes(objectToCheck, scheme, (errors, passedObject) => {
   if(errors) {
      console.log(errors)
   /*
      [ { propertyName: 'username',
          expectedType: 'String',
          recievedType: 'None',
          required: true } ]
   */
   } else {
      // do stuff with passedObject
})

Array type checking

const checkTypes = require("checktypes-js")

const [errors, returnedArray] = checkTypes([44, true, "a sexy string"], Array) // can also pass []

if (errors) {
  // handle errors
} else {
  // do stuff with returnedArray
}

Array with element type checking

const checkTypes = require("checktypes-js")

const [errors, passedArray] = checkTypes([44, "545", 11], [Number])

if (errors) {
  console.log(errors)
  /*
    [ { propertyName: '[1]',
        expectedType: 'Number',
        recievedType: 'String',
        required: false } ]
  */
} else {
  // do stuff with passedArray
}

String, Number, Boolean or Symbol type checking

const checkTypes = require("checktypes-js")

const someString = 55

const [error, passedItem] = checkTypes(someString, String)

if (error) {
  console.log(error)
  /*
    [ { propertyName: '' 
        expectedType: 'String',
        recievedType: 'Number',
        required: true } ]
  */
} else {
  // do stuff with passedItem
}

When type checking primitive types or when an Object or Array type mismatches at the parent/root level, the error object will have an empty string '' for the propertyName as it's not a property where the error occured. Also, the parent/root level is always required. You wouldn't be type checking if you didn't need it ;)

Helper Functions

This library provides a few helper functions to help you come up with innovative ways to handle errors. User your imagination!

getVal()

Use this helper function to get a value within the passed Object or Array using propertyName String.

getVal({PassedItem Object|Array}, {PropertyName String}, {StepBack: Number})

example:

const checkTypes = require("checktypes-js")
const { getVal } = checkTypes

const scheme = {
  request: {
    headers: [{ name: String, value: String }],
    type: String,
    body: String,
    statusCode: Number
  }
}

const requestObject = {
  requestDetails: {
    headers: [
      { name: "Authentication", value: "Bearer ..." },
      { name: "Content-Type", value: "application/json" },
      { name: "Cache-Control", value: 0 } // ERROR! value should be String type
    ],
    type: "POST",
    body: "...",
    statusCode: 200
  }
}

checkTypes(requestObject, scheme, function(errors, passedObject) {
  if (errors) {
    console.log(errors)
    /*
      [ { propertyName: 'request.headers[2]value',
          expectedType: 'String',
          recievedType: 'Number',
          required: false } ]
    */
    const value = getVal(passedObject, errors[0].propertyName)
    console.log(value)
    // 0

    /*   Or if you want encompassing object use stepBack (3rd argument)   */

    const objectValue = getVal(passedObject, errors[0].propertyName, 1)
    console.log(objectValue)
    // { name: "Cache-Control", value: 0 }
  } else {
    // do stuff with passedObject
  }
})

You can use the stepBack argument to step X properties back. So if you want to access the whole requestDetails object in above example, stepBack using stepBack set to 3. If you set stepBack farther than the number of properties that exist, function will throw an Error.

setVal()

Use this helper function to set a new value within the passed Object or Array using propertyName String.

setVal({PassedItem Object|Array}, {PropertyName String},
       {NewValue String|Number|Boolean|Symbol|Object|Array},
       {StepBack: Number})

example:

const checkTypes = require("checktypes-js")
const { getVal, setVal } = checkTypes

const scheme = {
  request: {
    headers: [{ name: String, value: String }],
    type: String,
    body: String,
    statusCode: Number
  }
}

const requestObject = {
  requestDetails: {
    headers: [
      { name: "Authentication", value: "Bearer ..." },
      { name: "Content-Type", value: "application/json" },
      { name: "Cache-Control", value: 0 } // ERROR! value should be String type
    ],
    type: "POST",
    body: "...",
    statusCode: 200
  }
}

checkTypes(requestObject, scheme, function(errors, passedObject) {
  if (errors) {
    console.log(errors)
    /*
      [ { propertyName: 'request.headers[2]value',
          expectedType: 'String',
          recievedType: 'Number',
          required: false } ]
    */
    const { propertyName } = errors[0]
    const value = getVal(passedObject, propertyName)
    console.log(value)
    // 0
    if (!value) setVal(passedObject, propertyName, "no-cache")
    const changedValue = getVal(passedObject, propertyName)
    console.log(changedValue)
    // 'no-cache'
  } else {
    // do stuff with passedObject
  }
})

You can use stepBack argument 4th argument as a way to set value to the encompassing Object or Array. It is useful for cases as such:

const checkTypes = require("checktypes-js")
const { getVal, setVal } = checkTypes

const saleScheme = {
  order: {
    number: Number,
    items: [String],
    customer: {
      name: String,
      phone: String,
      address: {
        street: String,
        city: String,
        state: String,
        zipCode: String,
        country: String
      }
    }
  },
  shipment: {
    postmarkId: Number,
    departed: Number,
    service: String
  }
}

const aSale = {
  order: {
    number: 3453434,
    items: ["purse", "ring", "jacket"],
    customer: {
      name: "Hannah Medcraft",
      phone: "214-000-3443",
      address: {
        street: "123 Main St",
        city: "Dallas",
        state: "TX",
        zipCode: 72034,
        country: "USA"
      }
    }
  },
  shipment: {
    postmarkId: 3423452456675,
    departed: 15604955496,
    service: "UPS"
  }
}

checkTypes(aSale, saleScheme, function(errors, passedObject) {
  if (errors) {
    console.log(errors)
    /*
      [ { propertyName: 'order.customer.address.zipCode',
          expectedType: 'Number',
          recievedType: 'String',
          required: false } ]
    */
    const { propertyName } = errors[0]
    const wholeAddress = getVal(passedObject, propertyName, 1)
    console.log(wholeAddress)
    /*
      {
        street: '123 Main St',
        city: 'Dallas',
        state: 'TX',
        zipCode: 72034,
        country: 'USA'
      }  
    */
    const newValidatedAddress = validateAddress(wholeAddress)
    setVal(passedObject, propertyName, newValidatedAddress, 1)

    const changedValue = getVal(passedObject, propertyName, 1)
    console.log(changedValue)
    /*
      {
        street: '123 Main Steet N',
        city: 'Irving',
        state: 'TX',
        zipCode: '72034-3453',
        country: 'USA'
      }   
    */
  } else {
    // do stuff with passedObject
  }
})

getType()

Use this helper function to get the type of an item passed to it.

getType({PassedItem String|Number|Boolean|Symbol|Object|Array|Undefined|Null})

example:

const checkTypes = require("checktypes-js")
const { getType } = checkTypes

const type = getType({ lambaRocks: true })
console.log(type)
//  'Object'

// OR

const type = getType(67)
console.log(type)
//  'Number'

typeToString()

Use this helper function to convert a type to a string.

typeToString({PassedType String|Number|Boolean|Symbol|Object|Array})

example:

const checkTypes = require("checktypes-js")
const { typeToString } = checkTypes

const typeAsString = typeToString(Array)

console.log(type)
//  'Array'

stringToType()

Use this helper function to convert a string type to a Javascript type.

stringToType({TypeString String})

example:

const checkTypes = require("checktypes-js")
const { stringToType } = checkTypes

const returnedType = stringToType("Object")

console.log(Object === returnedType)
//  true

propsFromString()

Use this helper function to convert an accessor string to an array of property names (for use to traverse through an object if needed).

propsFromString({AccessorString String})

example:

const checkTypes = require("checktypes-js")
const { propsFromString } = checkTypes

const anAccessorString = "order[1]address.zipCode"
const propertiesArray = propsFromString(anAccessorString)

console.log(propertiesArray)
//  ['order', '1', 'address', 'zipCode']

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

License

MIT

Support

Please open ticket, no email.