Question

I am typing this at the PowerShell command line:

java -jar closure-compiler.jar --js temp1.js --js_output_file temp2.js

and it generates this error output:

temp1.js:359: WARNING - Suspicious code. The result of the 'getprop' operator is not being used.
$acms.x
^

0 error(s), 1 warning(s)

(I know exactly what’s wrong with the JavaScript: that’s not the issue here.)

I want to capture this error output. However, if I try:

$errs = java -jar closure-compiler.jar --js temp1.js --js_output_file temp2.js

$errs ends up empty. But then if I try:

java -jar closure-compiler.jar --js temp1.js --js_output_file temp2.js 2>errs.txt

errs.txt captures this:

java.exe : temp1.js:359: WARNING - Suspicious code. The result of the 'getprop' operator is not being used.
At line:1 char:5
+ java <<<<  -jar closure-compiler.jar --js temp1.js --js_output_file temp2.js 2>errs.txt
    + CategoryInfo          : NotSpecified: (temp1.js:359: W...not being used.:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

$acms.x
^



0
 error(s), 
1
 warning(s)

Clearly the error output from the closure compiler is getting interleaved with PowerShell error output.

Is there any way to just capture the closure compiler output?

Answer 1

If you are doing:

$errs = command 2>&1

$errs.Exception will give you the message.

If only the error ( and only one) occured, $errs will have an ErrorRecord and you will be able to do the above and get the error that you want.

Otherwise, it will be an array of errorrecords and / or normal output.

So you will have to do

$errs | ?{$_.GetType().Name -eq "ErrorRecord"} | select -expand exception