Apply lazy resolution for engine's package.json

CHANGELOG.md

@@ -7,6 +7,10 @@
 - Upgrade Marp Core to [v3.5.0](https://github.com/marp-team/marp-core/releases/v3.5.0) ([#502](https://github.com/marp-team/marp-cli/pull/502))
 - Upgrade Node.js and dependent packages ([#502](https://github.com/marp-team/marp-cli/pull/502))
 
+### Fixed
+
+- Apply lazy resolution for engine's `package.json` ([#503](https://github.com/marp-team/marp-cli/pull/503))
+
 ## v2.3.0 - 2023-01-08
 
 ### Breaking

src/engine.ts

@@ -19,20 +19,16 @@ const delayedEngineResolver = (
 
 export class ResolvedEngine {
   klass: Engine
-  package?: Record<string, any>
+
+  private _cachedPackage?: Record<string, any> | null
 
   private static _defaultEngine: ResolvedEngine | undefined
 
   static async resolve(
     engine: ResolvableEngine | ResolvableEngine[],
     from?: string
   ): Promise<ResolvedEngine> {
-    const resolvedEngine = new ResolvedEngine(
-      await ResolvedEngine.resolveModule(engine, from)
-    )
-
-    await resolvedEngine.resolvePackage()
-    return resolvedEngine
+    return new ResolvedEngine(await ResolvedEngine.resolveModule(engine, from))
   }
 
   static async resolveDefaultEngine(): Promise<ResolvedEngine> {
@@ -51,6 +47,13 @@ export class ResolvedEngine {
     return ResolvedEngine._defaultEngine
   }
 
+  async getPackage() {
+    if (this._cachedPackage === undefined) {
+      this._cachedPackage = await this.resolvePackage()
+    }
+    return this._cachedPackage
+  }
+
   private static async resolveModule(
     engine: ResolvableEngine | ResolvableEngine[],
     from?: string
@@ -83,14 +86,15 @@ export class ResolvedEngine {
     this.klass = klass
   }
 
-  private async resolvePackage(): Promise<void> {
+  private async resolvePackage() {
     const classPath = this.findClassPath(this.klass)
-    if (!classPath) return
+    if (!classPath) return null
 
     const pkgPath = await pkgUp({ cwd: path.dirname(classPath) })
-    if (!pkgPath) return
+    if (!pkgPath) return null
 
-    this.package = require(pkgPath)
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    return require(pkgPath) as Record<string, any>
   }
 
   // NOTE: It cannot test because of overriding `require` in Jest context.

src/version.ts

@@ -4,21 +4,23 @@ import { MarpCLIConfig } from './config'
 import { ResolvedEngine } from './engine'
 
 export const isMarpCore = async (engine: ResolvedEngine): Promise<boolean> =>
-  engine.package?.name === '@marp-team/marp-core' ||
+  (await engine.getPackage())?.name === '@marp-team/marp-core' ||
   engine === (await ResolvedEngine.resolveDefaultEngine())
 
 export default async function outputVersion(config: MarpCLIConfig): Promise<0> {
   let engineVer = ''
+
   const { engine } = config
+  const enginePackage = await engine.getPackage()
 
   if (await isMarpCore(engine)) {
     engineVer = `@marp-team/marp-core v${bundledCoreVer}`
 
-    if (engine.package && engine.package.version !== bundledCoreVer) {
-      engineVer = `user-installed @marp-team/marp-core v${engine.package.version}`
+    if (enginePackage && enginePackage.version !== bundledCoreVer) {
+      engineVer = `user-installed @marp-team/marp-core v${enginePackage.version}`
     }
-  } else if (engine.package?.name && engine.package.version) {
-    engineVer = `customized engine in ${engine.package.name} v${engine.package.version}`
+  } else if (enginePackage?.name && enginePackage.version) {
+    engineVer = `customized engine in ${enginePackage.name} v${enginePackage.version}`
   } else {
     engineVer = `customized engine`
   }