URQL Scalars Exchange

urql exchange to allow mapping of custom scalar types

Example

pnpm add urql-scalars-exchange

or

npm install --save urql-scalars-exchange

Define a custom scalar like Json in your schema via:

scalar Json

Download the introspection query from your endpoint. See the urql docs for a script to download the schema from your endpoint.

Or, you can use an introspection .ts file genereated by graphql-codegen or gql.tada.

Configure the exchange like so

import customScalarsExchange from 'urql-scalars-exchange'
import schema from '../schema.json'
// or `import { schema } from '../introspection.ts`

const scalarsExchange = customScalarsExchange({
	schema: schema,
	scalars: {
		Json(value) {
			return JSON.parse(value)
		},
	},
})

Finally add the exchange to your urql client like so

const client = createClient({
	url: 'http://localhost:1234/graphql',
	exchanges: [dedupExchange, scalarsExchange, fetchExchange],
})

FAQ

Should this exchange be listed before or after the cache exchange?

This exchange should be listed before any cache exchange. Cache exchanges should represent the the data as returned by the endpoint.

Local Development

Below is a list of commands you will probably find useful.

npm run build or pnpm build

Bundles the package to the dist folder. The package is optimized and bundled with Rollup into multiple formats (CommonJS, UMD, and ES Module).

npm test or pnpm test

Runs the test watcher (vitest) in an interactive mode.

Acknowledgements

This project is an updated fork of the urql-custom-scalars-exchange project.

I have incorporated the changes made in the following PRs, so credit goes to the respective authors (thanks !):

• https://github.com/clentfort/urql-custom-scalars-exchange/pull/27 @mvarendorff
• https://github.com/clentfort/urql-custom-scalars-exchange/pull/25 @OzTK
• https://github.com/clentfort/urql-custom-scalars-exchange/pull/23 @DarryQueen

and @rwe for offering some advice and review on those PRs.