I really love TypeScript.
I started out with version 0.8 in VS 2010 because of a (mostly) client-side web project. I always tried to avoid JavaScript because I prefer programming languages that compile, and I found that finally TypeScript was the way to go.
Projects live on, and VS 2013 got installed on the PC, along with (manually installed) TypeScript 1.4. Now colleagues are already on VS 2015, and we need to have the same TypeScript compiler. So which version of TypeScript does Visual Studio use?

No indication that version 1.4 is installed
As far as I’m aware, VS 2013 does not provide the means to display the currently used TypeScript version. Answers to a related question on SO suggest to
- open cmd and run
tsc -v
- use VS Command Prompt and run
tsc -v
- open the Package Manager Console and run
tsc -v
but the always result in the message
Unknown option ‘v’
What’s going on here?
TypeScript is installed under C:\Program Files\Microsoft SDKs\TypeScript
(or C:\Program Files (x86)\Microsoft SDKs\TypeScript
on 64-bit Windows). To my surprise, I found 3 versions installed: 0.8.0.0, 1.0, 1.4, but the list of installed software in Programs and Features only listed 0.8.0.0 (“TypeScript for Microsoft VS 2012”) and 1.4.
Where did TypeScript version 1.0 come from? Apparently it got installed while applying VS2013 Update 5, judging from the directory timestamps. Oops: It might also have been installed with VS2013, and some timestamps updated during upgrade.
Different versions, different help message
This is the output if you run tsc from the directory 0.8.0.0:
Syntax: tsc [options] [file ..] Examples: tsc hello.ts tsc --out foo.js foo.ts tsc @args.txt Options: -c, --comments Emit comments to output --declarations Generates corresponding .d.ts file -e, --exec Execute the script after compilation -h, --help Print this message --module KIND Specify module code generation: "commonjs" (default) or "amd" --nolib Do not include a default lib.d.ts with global declarations --out FILE Concatenate and emit output to single file --target VER Specify ECMAScript target version: "ES3" (default), or "ES5" @<file> Insert command line options and files from a file. Note that there is no '-v' option!
This is the output of tsc run from directory 1.0:
Version 1.0.3.0 Syntax: tsc [options] [file ..] Examples: tsc hello.ts tsc --out foo.js foo.ts tsc @args.txt Options: --codepage NUMBER Specify the codepage to use when opening source files. -d, --declaration Generates corresponding .d.ts file. -h, --help Print this message. --mapRoot LOCATION Specifies the location where debugger should loc ate map files instead of generated locations. -m KIND, --module KIND Specify module code generation: 'commonjs' or 'a md' --noImplicitAny Warn on expressions and declarations with an imp lied 'any' type. --out FILE Concatenate and emit output to single file. --outDir DIRECTORY Redirect output structure to the directory. --removeComments Do not emit comments to output. --sourcemap Generates corresponding .map file. --sourceRoot LOCATION Specifies the location where debugger should loc ate TypeScript files instead of source locations. -t VERSION, --target VERSION Specify ECMAScript target version: 'ES3' (defaul t), or 'ES5' -v, --version Print the compiler's version: 1.0.3.0 @<file> Insert command line options and files from a fil e.
tsc -v results in
Version 1.0.3.0
This is the output of tsc run from directory 1.4:
Version 1.4.0.0 Syntax: tsc [options] [file ...] Examples: tsc hello.ts tsc --out file.js file.ts tsc @args.txt Options: -d, --declaration Generates corresponding '.d.ts' file. -h, --help Print this message. --mapRoot LOCATION Specifies the location where debugger should locate map files instead of generated locations. -m KIND, --module KIND Specify module code generation: 'commonjs' or 'amd' --noEmitOnError Do not emit outputs if any type checking erro rs were reported. --noImplicitAny Warn on expressions and declarations with an implied 'any' type. --out FILE Concatenate and emit output to single file. --outDir DIRECTORY Redirect output structure to the directory. --preserveConstEnums Do not erase const enum declarations in gener ated code. --removeComments Do not emit comments to output. --sourceMap Generates corresponding '.map' file. --sourceRoot LOCATION Specifies the location where debugger should locate TypeScript files instead of source locations. --suppressImplicitAnyIndexErrors Suppress noImplicitAny errors for indexing ob jects lacking index signatures. -t VERSION, --target VERSION Specify ECMAScript target version: 'ES3' (def ault), 'ES5', or 'ES6' (experimental) -v, --version Print the compiler's version. -w, --watch Watch input files. @<file> Insert command line options and files from a file.
tsc -v results in
message TS6029: Version 1.4.0.0
Due to whatever installation magic the installers perform, the PATH environment variable contains the directories related to TypeScript in this order:
C:\Program Files\Microsoft SDKs\TypeScript\0.8.0.0\; C:\Program Files\Microsoft SDKs\TypeScript\1.0\; C:\Program Files\Microsoft SDKs\TypeScript\1.4\;
which explains why the oldest version of TypeScript is called when invoked from command line.
This sequence is the same in Visual Studio Command Prompt (2010), which is OK due to compatibility. But the Developer Command prompt for VS2013 prepends version 1.0, resulting in
C:\Program Files\Microsoft SDKs\TypeScript\1.0\; C:\Program Files\Microsoft SDKs\TypeScript\0.8.0.0\; C:\Program Files\Microsoft SDKs\TypeScript\1.0\; C:\Program Files\Microsoft SDKs\TypeScript\1.4\;
This is because the VsDevCmd.bat – which initializes all VS-related paths and environment variables – checks for version 1.0, but no higher version:
@rem Add path to TypeScript Compiler @if exist "%ProgramFiles%\Microsoft SDKs\TypeScript\1.0" set PATH=%ProgramFiles%\Microsoft SDKs\TypeScript\1.0;%PATH% @if exist "%ProgramFiles(x86)%\Microsoft SDKs\TypeScript\1.0" set PATH=%ProgramFiles(x86)%\Microsoft SDKs\TypeScript\1.0;%PATH%
And my project?
And just in case you’re wondering which version of TypeScript your project is using, open its .csproj file in a text editor and search for TypeScript:
<TypeScriptToolsVersion>1.4</TypeScriptToolsVersion>
Blogger Allen Conway had similar experience regarding this question.