@envelop/on-resolve

@envelop/on-resolve

This plugin allows you to hook into resolves of every field in the GraphQL schema.

Useful for tracing or augmenting resolvers (and their results) with custom logic.

Getting Started

``
yarn add @envelop/on-resolve
`

Usage Example

$3

`ts
import { execute, parse, specifiedRules, subscribe, validate } from 'graphql'
import { envelop, useEngine } from '@envelop/core'
import { useOnResolve } from '@envelop/on-resolve'
import { specialResolver } from './my-resolvers'

const getEnveloped = envelop({
plugins: [
useEngine({ parse, validate, specifiedRules, execute, subscribe }),
// ... other plugins ...
useOnResolve(async function onResolve({ context, root, args, info, replaceResolver }) {
// replace special field's resolver
if (info.fieldName === 'special') {
replaceResolver(specialResolver)
}

// replace field's result
if (info.fieldName === 'alwaysHello') {
return ({ setResult }) => {
setResult('hello')
}
}
})
]
})
`

$3

`ts
import { execute, parse, specifiedRules, subscribe, validate } from 'graphql'
import { envelop, Plugin, useEngine } from '@envelop/core'
import { useOnResolve } from '@envelop/on-resolve'

interface FieldTracingPluginContext {
tracerUrl: string
}

function useFieldTracing() {
return {
onPluginInit({ addPlugin }) {
addPlugin(
useOnResolve(async function onResolve({ context, root, args, info }) {
await fetch(context.tracerUrl, {
method: 'POST',
headers: {
'content-type': 'application/json'
},
body: JSON.stringify({
startedResolving: {
...info,
parent: root,
args
}
})
})

return async () => {
await fetch(context.tracerUrl, {
method: 'POST',
headers: {
'content-type': 'application/json'
},
body: JSON.stringify({
endedResolving: {
...info,
parent: root,
args
}
})
})
}
})
)
}
}
}

const getEnveloped = envelop({
plugins: [
useEngine({ parse, validate, specifiedRules, execute, subscribe }),
// ... other plugins ...
useSpecialResolve()
]
})
``