gql-typeguards
v1.1.1
Published
GraphQL typeguards functions
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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