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https://github.com/prantlf/graphql-resolvable-directive
Supports GraphQL custom directives that hook into the field execution.
https://github.com/prantlf/graphql-resolvable-directive
directive field graphql graphql-directive resolve schema
Last synced: about 1 month ago
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Supports GraphQL custom directives that hook into the field execution.
- Host: GitHub
- URL: https://github.com/prantlf/graphql-resolvable-directive
- Owner: prantlf
- License: mit
- Created: 2019-08-18T14:19:54.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2019-12-29T20:00:15.000Z (about 5 years ago)
- Last Synced: 2024-11-16T12:44:36.992Z (2 months ago)
- Topics: directive, field, graphql, graphql-directive, resolve, schema
- Language: JavaScript
- Size: 129 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# graphql-resolvable-directive
[](http://badge.fury.io/js/graphql-resolvable-directive)
[](https://travis-ci.org/prantlf/graphql-resolvable-directive)
[](https://coveralls.io/github/prantlf/graphql-resolvable-directive?branch=master)
[](https://codeclimate.com/github/prantlf/graphql-resolvable-directive/maintainability)
[](https://codebeat.co/projects/github-com-prantlf-graphql-resolvable-directive-master)
[](https://david-dm.org/prantlf/graphql-resolvable-directive#info=devDependencies)
[](https://standardjs.com)
[](https://www.npmjs.com/package/graphql-resolvable-directive)
Supports GraphQL custom directives that hook into the field execution. It can be used for validation or transformation of the resulting field values.
## Synopsis
```js
const {
GraphQLResolvableDirective, supportResolvableDirectives
} = require('graphql-resolvable-directive')
// Performs the logical negation on the field value.
const notDirective = new GraphQLResolvableDirective({
name: 'not',
description: 'Negates the field execution result.',
locations: [DirectiveLocation.FIELD],
async resolve (resolve, source, args, context, info) {
const result = await resolve()
return !result
}
})
// Exposes a single field "falsy" returning the `null` value.
// Recognizes the `not` directive.
const schema = new GraphQLSchema({
directives: [notDirective],
query: new GraphQLObjectType({
name: 'Query',
fields: () => ({
falsy: { type: GraphQLBoolean }
})
})
})
visitFields(schema, field => supportCustomDirectives(field, schema))
// Returns `true` instead of the default `null`.
const { data } = await graphql(schema, '{ falsy @not }')
assert(data.falsy)
```
## Installation
This module can be installed in your project using [NPM] or [Yarn]. Make sure, that you use [Node.js] version 8 or newer.
```sh
$ npm i graphql-resolvable-directive -S
```
```sh
$ yarn add graphql-resolvable-directive
```
## Description
### GraphQLResolvableDirective
Base class for custom directives with field execution hooks. If they include the `resolve` method, it will be called instead of the original field resolver. It would usually call the original resolver to inspect or modify its result.
```js
const { GraphQLResolvableDirective } = require('graphql-resolvable-directive')
const isTruthyDirective = new GraphQLResolvableDirective({
name: 'isTruthy',
description: 'Checks if the field execution result is truthy.',
locations: [DirectiveLocation.FIELD],
async resolve (resolve, source, args, context, info) {
const result = await resolve()
if (!result) {
throw new Error(`The field "${info.fieldName}" was not truthy.`)
}
return result
}
})
const toLowerCaseDirective = new GraphQLResolvableDirective({
name: 'toLowerCase',
description: 'Converts a string value to lower-case.',
locations: [DirectiveLocation.FIELD],
async resolve (resolve, source, args, context, info) {
const result = await resolve()
return result.toLowerCase()
}
})
```
If the directives are chained, the results are passed from the first directive to the next one and so on. The last returned value is assigned to the field.
```js
graphql(schema, '{ name @isTruthy @toLowerCase }')
```
### supportCustomDirectives(field, schema)
Enables hooking into the field execution by a custom directive for the specified field. Directives have to be provided in the schema configuration.
* `field` has to be a field configuration object
* `schema` has to be an object instance of the type `GraphQLSchema`
Field configurations are usually obtained from a schema by a field visitor like [graphql-field-visitor], for example.
```js
const { supportResolvableDirectives } = require('graphql-resolvable-directive')
const { visitFields } = require('graphql-field-visitor')
const schema = new GraphQLSchema({
directives: [isTruthyDirective, toLowerCaseDirective],
query: ...
})
visitFields(schema, field => supportCustomDirectives(field, schema))
```
## Contributing
In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.
## Release History
* 2019-08-18 v0.0.1 Initial release
## License
Copyright (c) 2019 Ferdinand Prantl
Licensed under the MIT license.
[Node.js]: http://nodejs.org/
[NPM]: https://www.npmjs.com/
[Yarn]: https://yarnpkg.com/
[graphql-field-visitor]: https://github.com/prantlf/graphql-field-visitor