relay-compiler-language-scalajs

0.41.0 verified Fri May 01 auth: no javascript

A Relay compiler language plugin that generates Scala.js bindings (js.native traits) instead of Flow types for GraphQL-driven Scala.js applications. Compatible with Relay 11.0.2, graphql ^15.4.0, and relay-runtime ^11.0.2. The plugin outputs compiled queries as Scala.js native traits, supports custom output via @scalajs directives (extends, useNulls), and uses artifactDirectory for flat package generation. Release cadence is irregular with minor version bumps for dependency updates. Differentiator: enables Relay for Scala.js/React.js integration, not maintained by the core Relay team.

Common errors

error Error: Cannot find module 'relay-compiler-language-scalajs' ↓

cause Missing npm install of the package

fix

Run: npm install --save-dev relay-compiler-language-scalajs

error Error: The language 'scalajs' is not supported. ↓

cause relay-compiler version mismatch or missing plugin

fix

Ensure relay-compiler@11.0.2 is installed and package is in node_modules.

error Error: No schema found at --schema path ↓

cause Invalid or missing GraphQL schema file

fix

Provide valid .graphql schema path via --schema.

error Error: Could not parse GraphQL file: unexpected directive ↓

cause Using @scalajs on unsupported GraphQL elements

fix

Only use @scalajs on fragments, fields, or inline fragments.

Warnings

gotcha Requires exact Relay version 11.0.2; other versions may break. ↓

fix Ensure relay-compiler version is pinned to 11.0.2.

gotcha Uses artifactDirectory flat layout; all generated files in one directory. ↓

fix Configure artifactDirectory to a dedicated output directory, not mixed with sources.

deprecated The @scalajs(extends) directive requires manual verification of parent class. ↓

fix Ensure the extended class exists in Scala.js scope.

gotcha graphql peer dependency must be ^15.4.0, not newer GraphQL versions. ↓

fix Use GraphQL 15.4.x or compatible.

Install

npm install relay-compiler-language-scalajs

yarn add relay-compiler-language-scalajs

pnpm add relay-compiler-language-scalajs

Imports

relay-compiler
wrong
```
No direct JS import; used via CLI
```
correct
```
import 'relay-compiler' (see docs)
```
This is a compiler language plugin; no JavaScript import. Configure via relay-compiler --language scalajs.
@scalajs
wrong
```
Not a JavaScript import
```
correct
```
Used as GraphQL directive in .graphql files
```
Use as @scalajs(extends: String) or @scalajs(useNulls: Boolean) on GraphQL fragments/fields.
relay-runtime
wrong
```
Missing peer dep
```
correct
```
npm install relay-runtime
```
Required at runtime for Relay queries; version ^11.0.2.

Quickstart

Installs required packages and shows relay-compiler invocation to generate Scala.js bindings.

// 1. Install dependencies
npm install --save-dev relay-compiler@11.0.2 relay-compiler-language-scalajs graphql@^15.4.0
npm install relay-runtime@^11.0.2

// 2. Run relay-compiler with scalajs language
// ./node_modules/.bin/relay-compiler --language scalajs --src ./src --schema ./schema.graphql --artifactDirectory ./src/__generated__

// 3. Generated Scala.js file (example: src/__generated__/MyFragment.scala)
@js.native
trait MyFragment_data extends js.Object {
  val id: String = js.native
  val name: String | Null = js.native
}