Write compiled output to stdout

[jbowens]

It doesn't seem possible to compile and output to stdout. There was some discussion on CodePlex before the migration to github: https://typescript.codeplex.com/workitem/600

[mhegazy]

Would a node package of the compiler with an API that allows you to pass strings and get strings back do the job?

[jbowens]

That'd definitely be useful, but I'd much rather have an option to output to stdout in the cli.

[mhegazy]

so what happens if you have multiple outputs? how do you indicate file begin and end? and where do errors go? or should it just be a JSON.stringify output?

[jbowens]

I think it'd be reasonable to only support --out functionality when printing to stdout, so it would print the concatenation of all outputs. Errors should be written to stderr.

It'd also be nice if it could take input through stdin, so tsc could be used in a series of commands using unix pipes.

[DanielRosenwasser]

If you're on a Unix system, you can look into mkfifo as a temporary workaround. I _think_ the following might work.

mkfifo -m 600 my_fifo
tsc file1.ts file2.ts --out my_fifo
YOUR_COMMAND_HERE < my_fifo
# or...
cat my_fifo | YOUR_COMMAND_HERE

but I can admittedly see the utility in having standard output as a target.

[RyanCavanaugh]

Open questions:

• What should we call the flag?
• What happens to external module emit? We currently emit those to their own file even under --out. It might be desirable to be compiling a single external module under this flag, so we wouldn't want to error, but we may also end up compiling more than one external module (and thus emitting more than one file).

[DanielRosenwasser]

Another question: how do you differentiate between output and message output? I guess we could use standard error as well.

[mklement0]

What should we call the flag?

Following @jbowens's suggestion to invariably apply --out behavior, there doesn't have to be a new flag: the Unix (POSIX) convention of using - to represent stdin or stdout (as in this case), could be applied: tsc --out - ....

While there's a hypothetical backward-compatibility concern -- currently, tsc literally creates a file named -, if you do that -- I don't think anyone would miss it.

As for the "Unix-centricness": I wouldn't expect Windows users to object, either.

[mnpenner]

I wanted this functionality for compiling little inline snippets of TypeScript within my templates which I could inject back into <script> tags. I wouldn't use it for anything that generated multi-file output.

[mhegazy]

have you considered typestring?