feat: Custom tsconfig.json, credits to @Knaackee

README.md

@@ -54,6 +54,19 @@ The default `tsconfig.json` file used by the plugin looks like this:
 
 > Note 2: Don't confuse the [`tsconfig.json`](tsconfig.json) in this repository with the one mentioned above.
 
+### Custom Typescript Configuration
+
+This plugin will use your local `tsconfig.json` if it exists. You can configure a path to a custom Typescript configuration inside your `serverless.yml` using:
+
+    ...
+    plugins:
+      - serverless-plugin-typescript
+    custom:
+      typeScript:
+        tsconfigFilePath: ./tsconfig.build.json
+    ...    
+
+
 ### Including extra files
 
 All files from `package/include` will be included in the final build file. See [Exclude/Include](https://serverless.com/framework/docs/providers/aws/guide/packaging#exclude--include)

src/Serverless.d.ts

@@ -12,6 +12,11 @@ declare namespace Serverless {
       provider: {
         name: string
       }
+      custom: {
+        typeScript: {
+          tsconfigFilePath: string | undefined
+        }
+      },
       functions: {
         [key: string]: Serverless.Function
       }

src/index.ts

@@ -118,7 +118,7 @@ export class TypeScriptPlugin {
     this.serverless.cli.log(`Watch function ${this.options.function}...`)
 
     this.isWatching = true
-    watchFiles(this.rootFileNames, this.originalServicePath, () => {
+    watchFiles(this.rootFileNames, this.originalServicePath, this.serverless, () => {
       this.serverless.pluginManager.spawn('invoke:local')
     })
   }
@@ -131,7 +131,7 @@ export class TypeScriptPlugin {
     this.serverless.cli.log(`Watching typescript files...`)
 
     this.isWatching = true
-    watchFiles(this.rootFileNames, this.originalServicePath, this.compileTs.bind(this))
+    watchFiles(this.rootFileNames, this.originalServicePath, this.serverless, this.compileTs.bind(this))
   }
 
   async compileTs(): Promise<string[]> {
@@ -147,6 +147,7 @@ export class TypeScriptPlugin {
 
     const tsconfig = typescript.getTypescriptConfig(
       this.originalServicePath,
+      this.serverless,
       this.isWatching ? null : this.serverless.cli
     )
 

src/typescript.ts

@@ -112,9 +112,17 @@ export function getSourceFiles(
 
 export function getTypescriptConfig(
   cwd: string,
+  serverless?: Serverless.Instance,
   logger?: { log: (str: string) => void }
 ): ts.CompilerOptions {
-  const configFilePath = path.join(cwd, 'tsconfig.json')
+  let configFilePath = path.join(cwd, 'tsconfig.json')
+
+  if (serverless && serverless.service.custom && serverless.service.custom.typeScript && serverless.service.custom.typeScript.tsconfigFilePath) {
+    configFilePath = path.join(cwd, serverless.service.custom.typeScript.tsconfigFilePath)
+    if (!fs.existsSync(configFilePath)) {
+      throw new Error(`Custom Typescript Config File not found at "${configFilePath}"`)
+    }
+  }
 
   if (fs.existsSync(configFilePath)) {
 
@@ -130,7 +138,7 @@ export function getTypescriptConfig(
     }
 
     if (logger) {
-      logger.log(`Using local tsconfig.json`)
+      logger.log(`Using local tsconfig.json "${configFilePath}"`)
     }
 
     // disallow overrriding rootDir

src/watchFiles.ts

@@ -1,8 +1,13 @@
 import * as typescript from './typescript'
-import { watchFile, unwatchFile, Stats} from 'fs'
+import { watchFile, unwatchFile, Stats } from 'fs'
 
-export function watchFiles(rootFileNames: string[], originalServicePath: string, cb: () => void) {
-  const tsConfig = typescript.getTypescriptConfig(originalServicePath)
+export function watchFiles(
+  rootFileNames: string[],
+  originalServicePath: string,
+  serverless: Serverless.Instance,
+  cb: () => void
+) {
+  const tsConfig = typescript.getTypescriptConfig(originalServicePath, serverless)
   let watchedFiles = typescript.getSourceFiles(rootFileNames, tsConfig)
 
   watchedFiles.forEach(fileName => {
@@ -18,7 +23,7 @@ export function watchFiles(rootFileNames: string[], originalServicePath: string,
     cb()
 
     // use can reference not watched yet file or remove reference to already watched
-    const newWatchFiles =  typescript.getSourceFiles(rootFileNames, tsConfig)
+    const newWatchFiles = typescript.getSourceFiles(rootFileNames, tsConfig)
     watchedFiles.forEach(fileName => {
       if (newWatchFiles.indexOf(fileName) < 0) {
         unwatchFile(fileName, watchCallback)

tests/custom.tsconfig.json

@@ -0,0 +1,5 @@
+{
+    "compilerOptions": {
+        "target": "es6"
+    }
+}

tests/typescript.getTypescriptConfig.test.ts

@@ -8,4 +8,30 @@ describe('getTypescriptConfig', () => {
             makeDefaultTypescriptConfig()
         )
     })
+
+    it (`should throw an error if configured typescript configuration does not exist`, () => {
+        expect(() =>
+            getTypescriptConfig(process.cwd(), { 
+                service: {
+                    custom: {
+                        typeScript: {
+                            tsconfigFilePath: "./some-path"
+                        }
+                    }}
+                } as any),
+        ).toThrowError("Custom Typescript Config File not found")
+    })
+
+    it (`returns configured typescript configuration if provided`, () => {
+        expect(
+            getTypescriptConfig(process.cwd(), { 
+                service: {
+                    custom: {
+                        typeScript: {
+                            tsconfigFilePath: "./tests/custom.tsconfig.json"
+                        }
+                    }}
+                } as any).target,
+        ).toEqual(2)
+    })
 })