tsc -w should clear screen before each run

[k0pernikus]

Run compiler in watch mode: tsc -w. Change some files, causing multiple compilations.

Expected behavior:

As a developer, I expect the output of tsc -w to be relevant and concise to the current runtime. It should show me the information only of the current run, stating that either the compilation was a success or fail with an error message.

Actual behavior:

The output of previous compilations is kept.

Benefit:

During development, seeing old output is redundant, noisy, and it also takes away if there are errors in the output as I am not alarmed to them right away. They could simply have been errors from the last run.

I have to manually enter new lines or check the timestamps. I have to parse the output what error messages relate to which run. I am discovering myself hitting enter multiple times to create distinguishable marks so that I better see the output of the next run. Sometimes I just cancel watch mode and run tsc multiple times manually while debugging an issue.

Another tool that has a similar feature to what I am proposing is mocha with their min reporter.

[RyanCavanaugh]

Accepting PRs - should be straightforward. Add a cls method to sys; we'll take care of implementing it for tsc.exe

[GongT]

on linux, I m using this for a lone time:

function tscp {
        echo -en "\ec\0typescript compiling (source: $1)...\r"
        tsc -w -p "$1" | sed 's/^.*File change detected/\x1Bc\0/g'
}

cmd.exe also support "\x1Bc" ( c ), at least on win10.

[mhegazy]

Fixed by #20389