Getting Cannot compile modules using option 'outFile' unless the '--module' flag is 'amd' or 'system'

Question

I am writing an import statement import { PI } from './math/circle' in app.ts file and have a constant export const PI = 3.14 in circle.ts file but on running the program by doing tsc app.ts --outFile app.js keeps showing this error.

error TS6131: Cannot compile modules using option 'outFile' unless the '--module' flag is 'amd' or 'system'. 1 export const PI = 3.14

But according to the docs I am importing correctly. I have also tried changing the "module": "commonjs" to "module": "amd"/"system" and then reloading the VSCode windows but no luck. Where am I going wrong?

tsconfig.json

{
  "compilerOptions": {    
    "target": "es5",                         
    "module": "amd",                    
    "strict": true,                          
    "noImplicitAny": true,                
    "strictNullChecks": true,              
    "strictPropertyInitialization": false
  },
  "exclude": [
    "node_modules"
  ]
}

P.S: typescript version 3.5.3

Answer 1

If you want your tsconfig.json to be taken into account you have to invoque the tsc command with no input files, more details here. Running tsc app.ts --outFile app.js you are skipping your tsconfig.json and therefore you have to specify the module system manually so running tsc app.ts --outFile app.js --module amd should do the trick.

The other option as mentioned above is just to run tsc --outFile app.js.

Answer 2

You should be using a tool like webpack to bundle multiple typescript files into a single javascript file.