--all does not include .ts files that use typecasting

[nddeluca]

This one stumped me for a while on a typescript code base I added coverage too. I wasn't seeing all my source files being included when using --all, and narrowed it down to files that use the <T> or as T typecasting syntax. Seemed a bit strange, but I was able to set up a new repository and observe the issue in isolation (see below).

Note: This is only when using the -all flag. If one of the files that is affected is included in a test, then it shows up in the coverage report. Also, the typescript generic syntax (ex. function<T>()) does not have this issue either, so I don't believe it's related to the appearance of the brackets.

---

Expected Behavior

--all should include all .ts files

Observed Behavior

--all does not include .ts files that use typecasting

Bonus Points! Code (or Repository) that Reproduces Issue

See https://github.com/nddeluca/nyc-ts-test.

You can clone, npm install, and npm test to observe the issue.
There are three example .ts files named a, b, and c.

a gets included in the coverage report
b and c both use typecasting and get ignored.

If you edit the code and remove the typecasting, the files will show up in the coverage.

Forensic Information

Operating System: the operating system you observed the issue on.

Darwin Kernel Version 16.3.0

Environment Information: information about your project's environment, see instructions below:

Node 8.4.0
NPM 5.3.0
Typescript 2.4.2

[bcoe]

@nddeluca --all needs to be able to parse all of the files as it walks them. How are you transpiling the source?

If you're using something like typescript-register, make sure that it's nyc that requires typescript-register rather than your test framework.

[Edo78]

I had the vary same problem and solved it moving the require of ts-node/register from mocha to nyc.

Maybe it should be documented or if it's already then it should be easier to find.

[jonaskello]

I'm using tape with typescript and have this same problem. If I move the --require ts-node/register to nyc instead of tape I get this error: TypeError: Unable to require .d.ts file.

This is the same error as in #504. Actually in that issue, the solution is to move --require ts-node/register from nyc to mocha, and in this issue it the solution is the other way around 😕

[jonaskello]

I found a solution to my problem above. It is to put --require ts-node/register in nyc and exclude *.d.ts files. So my .nycrc.json now looks like this:

{
  "all": true,
  "include": ["src/*"],
  "exclude": ["src/index.ts", "**/*.d.ts"],
  "extension": [".ts"],
  "reporter": ["html", "lcov", "text"],
  "sourceMap": true,
  "require": ["ts-node/register"]
}

[Aqours]

@jonaskello how to include custom types when using nyc mocha ?

global.d.ts file included by tsconfig.json

declare const DEBUG: boolean;

index.ts

if (DEBUG) {
    console.log('debug');
}

It will throw an error error TS2304: Cannot find name 'DEBUG'. when I runing nyc mocha. It seems tsconfig.json not be used by ts-node. But it works fine if I put --require ts-node/register to mocha not nyc.

Solution: Use --require ts-node/register/transpile-only instead of --require ts-node/register

[JaKXz]

I've updated the TS tutorial that had some of the tips in here, with some of the newer tips. If you are able, please contribute to those docs :) https://github.com/istanbuljs/istanbuljs.github.io