graphql-fields

Turns GraphQLResolveInfo into a map of the requested fields. Flattens all fragments and duplicated fields into a neat object to easily see which fields were requested at any level. Takes into account any @include or @skip directives, excluding fields/fragments which are @include(if: $false) or @skip(if: $true).

Usage

Schema Type definition
``javascript
const graphqlFields = require('graphql-fields');
const graphql = require('graphql')

const UserType = new graphql.GraphQLObjectType({
name: 'User',
fields: {
profile: {type: new graphql.GraphQLObjectType({
name: 'Profile',
fields: {
firstName: {type: graphql.GraphQLString},
lastName: {type: graphql.GraphQLString},
middleName: {type: graphql.GraphQLString},
nickName: {type: graphql.GraphQLString},
maidenName: {type: graphql.GraphQLString}
}
}),
email: {type: graphql.GraphQLString},
id: {type: graphql.GraphQLID}
}
});

module.exports = new GraphQLSchema({
query: new GraphQLObjectType({
name: 'Query',
fields: () =>
Object.assign({
user: {
type: UserType,
resolve(root, args, context, info) {
console.log(
JSON.stringify(graphqlFields(info), null, 2);
);
...
}
}
})
})
})
`

Query
`graphql
{
user {
...A
profile {
...B
firstName
}
}
}

fragment A on User {
...C
id,
profile {
lastName
}
}

Fragment B on Profile {
firstName
nickName @skip(if: true)
}

Fragment C on User {
email,
profile {
middleName
maidenName @include(if: false)
}
}
`

will log
`json
{
"profile": {
"firstName": {},
"lastName": {},
"middleName": {}
},
"email": {},
"id": {}
}

`


$3

To enable subfields arguments parsing, you'll have to provide an option object to the function. This feature is disable by default.
`javascript
const graphqlFields = require('graphql-fields');
const fieldsWithSubFieldsArgs = graphqlFields(info, {}, { processArguments: true });
`

For each subfield w/ arguments, a __arguments property will be created.
It will be an array with the following format:
`javascript
[
{
arg1Name: {
kind: ARG1_KIND,
value: ARG1_VALUE,
},
},
{
arg2Name: {
kind: ARG2_KIND,
value: ARG2_VALUE,
}
}
]
`

The kind property is here to help differentiate value cast to strings by javascript clients, such as enum values.

$3


Most of the time we don't need __typename to be sent to backend/rest api, we can exclude __typename using this:
`javascript
const graphqlFields = require('graphql-fields');
const fieldsWithoutTypeName = graphqlFields(info, {}, { excludedFields: ['__typename'] });
`

Why

An underlying REST api may only return fields based on query params.
`graphql
{
user {
profile {
firstName
},
id
}
}
`
should request /api/user?fields=profile,id

while
`graphql
{
user {
email
}
}
`
should request /api/user?fields=email

Implement your resolve method like so:

`
resolve(root, args, context, info) {
const topLevelFields = Object.keys(graphqlFields(info));
return fetch(/api/user?fields=${topLevelFields.join(',')});
}
`

Tests


`
npm test
``