Compile time errors being suppressed when using esm #2129
Description
I really struggled to think of the correct title for this, so please edit it as required. I went down a rabbithole today whilst moving one of our apps to esm, as it was failing to start (with ts-node) due to the following node error:
❯ node --experimental-specifier-resolution=node --loader ts-node/esm lib/index.ts
node:internal/modules/run_main:115
triggerUncaughtException(
^
[Object: null prototype] {
[Symbol(nodejs.util.inspect.custom)]: [Function: [nodejs.util.inspect.custom]]
}
Node.js v22.5.1
Doesn't really give away much. It turned out however that the root caused we missed a return type on a promise eg Promise needed to be Promise<void>. This error was visible if you did a tsc, but ts-node was giving this output.
After gradually chipping away at the code to make a minimal example; i managed to reproduce it with a really simple bit of code that doesn't even technically have an error in it.
Assuming your code is in ./lib, create ./lib/index.ts:
import { SomeServer } from './server.js'
const webServer = new SomeServer()
and ./lib/server.ts:
export class SomeServer {}
If you try and start this; you'll get the error. The only thing "wrong" with this code is the fact that webServer is an unused variable. If i add console.log(webServer), eg:
import { SomeServer } from './server.js'
const webServer = new SomeServer()
console.log(webServer)
Then all is well:
❯ node --experimental-specifier-resolution=node --loader ts-node/esm lib/index.ts
SomeServer {}
Specifications
- versions:
❯ ./node_modules/.bin/ts-node -vv
ts-node v10.9.2
node v22.5.1
compiler v5.3.3
- tsconfig.json:
{
"compilerOptions": {
"lib": ["ES2022", "DOM"],
"module": "ES2022",
"target": "ES2022",
"rootDir": "./",
"outDir": "./built",
"baseUrl": "./",
"allowJs": false,
"checkJs": false,
"alwaysStrict": true,
"noImplicitAny": true,
"noImplicitThis": true,
"strictNullChecks": true,
"strictFunctionTypes": true,
"strictPropertyInitialization": true,
"noEmitOnError": false,
"sourceMap": false,
"declaration": false,
"strictBindCallApply": true,
"noImplicitOverride": true,
"noUncheckedIndexedAccess": true,
"incremental": false,
"skipDefaultLibCheck": true,
"experimentalDecorators": true,
"noUnusedLocals": true,
"esModuleInterop": true,
"moduleResolution": "node",
"emitDecoratorMetadata": true,
"allowSyntheticDefaultImports": true,
"forceConsistentCasingInFileNames": true,
"noFallthroughCasesInSwitch": true
},
"include": ["lib/**/*.ts", "test/**/*.ts"],
"exclude": ["node_modules/**/*"]
}
- Operating system and version: Mac