tasks.json

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "0.1.0",
    "command": "tsc",
    "isShellCommand": true,
    "args": [
        "--target","ES5", 
        "--outDir", "js", 
        "--module","commonjs",
        "--sourceMap", 
        "--watch", "app.ts"
        ],
    "showOutput": "silent",
    "problemMatcher":"$tsc"
}