Which Version of TypeScript does Visual Studio use?

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.