gql-typeguards
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1.1.1 • Public • Published

Gql-Typeguards

Gql-typeguards is a set of helpers typeguards functions aiming to improve the DX of GraphQL and Typescript projects.

Installation

npm i gql-typeguards
or
yarn add gql-typeguards

Functions

  • isType()
interface Object extends {
  name: 'object',
  __typename:  'Object'
}
interface OtherObject extends {
  title: 'other object',
  __typename: 'OtherObject'
}

isType(object,'__typenameValue'):boolean

// Usage
// type object = Object | OtherObject
if(isType(object, 'Object')) {
  // object.name will be infered as valid
}
  • isEither()
interface Object extends {
    name: 'object',
  __typename: 'Object'
}
interface OtherObject extends {
   name: 'other object',
  __typename: 'OtherObject'
}
interface AnotherObject extends {
   title: 'another object',
  __typename: 'AnotherObject'
}
// type object = Object | OtherObject | AnotherObject
isEither(object, ['Object', 'OtherObject']):boolean

// Usage
if(isEither(object, ['Object', 'OtherObject'])) {
  // object.name will be infered as valid
  // object.tile will be infered as undefined
}
  • isNot()
interface Object extends {
    name: 'object',
  __typename: 'Object'
}
interface OtherObject extends {
   name: 'other object',
  __typename: 'OtherObject'
}
interface AnotherObject extends {
   title: 'another object',
  __typename: 'AnotherObject'
}
// type object = Object | OtherObject | AnotherObject
isNot(object, ['Object', 'OtherObject']):boolean
// Usage
if(isNot(object, ['Object', 'OtherObject'])) {
  // object.name will be infered as undefined
  // object.tile will be infered as valid
}
  • isTypeInTuple()
interface Object extends {
  name: 'object',
  __typename: 'Object'
}
interface OtherObject extends {
  title: 'other object',
  __typename: 'OtherObject'
}
// type tuple = Array<Object | OtherObject>
const typedArrayOfObject = tuple.filter(isTypeInTuple('Object'))
const typedArrayfOtherObject = tuple.filter(isTypeInTuple('OtherObject'))

// Possible undefined
tuple[0].name
tuple[0].title

// Infered as valid
typedArrayOfObject[0].name

// Infered as valid
typedArrayfOtherObject[0].title
  • isEitherTypesInTuple()
interface Object extends {
  name: 'object',
  __typename: 'Object'
}
interface OtherObject extends {
  title: 'other object',
  __typename: 'OtherObject'
}

interface ThirdObject extends {
  content: 'third object',
  __typename: 'ThirdObject'
}

// type tuple = Array<Object | OtherObject | ThirdObject>
const typedArrayOfObjectOrOtherObject = tuple.filter(isEitherTypesInTuple(['Object', 'OtherObject']))

// Possible undefined
tuple[0].name
tuple[0].title

// Infered as valid
typedArrayOfObjectOrOtherObject[0].name

// Infered as valid
typedArrayOfObjectOrOtherObject[0].title

// Infered as invalid
typedArrayOfObjectOrOtherObject[0].content
  • isNotTypesInTuple()
interface Object extends {
  name: 'object',
  __typename: 'Object'
}
interface OtherObject extends {
  title: 'other object',
  __typename: 'OtherObject'
}

interface ThirdObject extends {
  content: 'third object',
  __typename: 'ThirdObject'
}

// type tuple = Array<Object | OtherObject | ThirdObject>
const typedArrayOfThirdObject = tuple.filter(isNotTypesInTuple(['Object', 'OtherObject']))

// Possible undefined
tuple[0].name
tuple[0].title

// Infered as invalid
typedArrayOfThirdObject[0].name

// Infered as invalid
typedArrayOfThirdObject[0].title

// Infered as valid
typedArrayOfThirdObject[0].content

Package Sidebar

Install

npm i gql-typeguards

Weekly Downloads

205

Version

1.1.1

License

MIT

Unpacked Size

23.8 kB

Total Files

15

Last publish

Collaborators

  • nicolastoulemont