Tracing module resolution

Tracing module resolution

As discussed earlier, the compiler can visit files outside the current folder when resolving a module. This can be hard when diagnosing why a module is not resolved, or is resolved to an incorrect definition. Enabling the compiler module resolution tracing using --traceResolution provides insight in what happened during the module resolution process.

Let’s say we have a sample application that uses the typescript module. app.ts has an import like import * as ts from "typescript".

Invoking the compiler with --traceResolution

Results in an output as such:

Things to look out for

• Name and location of the import

======== Resolving module ‘typescript’ from ‘src/app.ts’. ========

• The strategy the compiler is following

Module resolution kind is not specified, using ‘NodeJs’.

• Loading of typings from npm packages

‘package.json’ has ‘typings’ field ‘./lib/typescript.d.ts’ that references ‘node_modules/typescript/lib/typescript.d.ts’.

• Final result

======== Module name ‘typescript’ was successfully resolved to ‘node_modules/typescript/lib/typescript.d.ts’. ========