gulp-typescript rootdirs example

This example is intended to demonstrate discrepancies in the behavior between how the native typescript compiler and the typescript API handle the rootDirs tsconfig compiler option, specifically when the typescript API is called through the gulp-typescript plugin. I have not (at this time) created a testcase to indicate whether this is an issue with how I am using the gulp-typescript plugin, with how the gulp-typescript plugin is using the typescript API or with a discrepancy in how the typescript API delegates to the typescript compiler.

Simple Demonstration

note: the below commands will globally install typescript 2.0 (which was not the stable release at the time this project was created).

# 1. globally install typescript 2.0 (which supports the rootDirs configuration
npm install [email protected] -g

# echo 2. install this example's dependencies
npm install

# 3. confirm the typescript 2.0 compiler compiles without error
tsc

# 4. attempt the same compilation through the gulp-typescript plugin
gulp tsc

Expected Behavior

Steps 3 and 4 should behave identically

Actual Behavior

Step 3 compiles without warning or error while step 4 compiles with a semantic error.

Note

I'm fairly fresh to Typescript development, so it's very possible I'm doing something wrong or have an invalid expectation arising from a fundamental misunderstanding.