Watch mode in Typescript is not working in tasks.json

Question

I am using VisualStudio Code as my text editor. In my typescript project, I have a .vscode folder and inside that tasks.json file is present.
When I use the following configuration,

{
   "version": "0.1.0",
   "command": "tsc",
   "isShellCommand": true,
   "args": ["-p", "."],
   "showOutput": "silent",
   "problemMatcher": "$tsc"
}

the ts files are built correctly without any error.
I want to enable "compileOnSave" option so that i don't have to run build everytime. I also added watch paramater in tasks. After the changes, my files look like this.
tsconfig.json

{
   "compileOnSave": true,
   "compilerOptions": {
      "target": "es5",
      "module": "commonjs",
      "outDir": "jsFiles/",
      "sourceMap": true
   },
   "exclude": [
      "node_modules",
      "lib"
   ]
}  

tasks.json

{
   "version": "0.1.0",
   "command": "tsc",
   "isShellCommand": true,
   "args": ["-w", "-p", "."],
   "showOutput": "silent",
   "isBackground": true,
   "problemMatcher": "$tsc"
}  

But the above configuration throws an error like below:

fs.js:1402
throw error;
^
Error: watch . ENOSPC
    at exports._errnoException (util.js:1034:11)
    at FSWatcher.start (fs.js:1400:19)
    at Object.fs.watch (fs.js:1426:11)
    at Object.watchDirectory 
(/usr/lib/node_modules/typescript/lib/tsc.js:2377:32)
    at Object.executeCommandLine 
(/usr/lib/node_modules/typescript/lib/tsc.js:53355:43)
    at Object.<anonymous> 
(/usr/lib/node_modules/typescript/lib/tsc.js:53712:4)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
Watching build tasks has finished.  

I also tried to change problemMatcher: $tsc-watch, removing isBackground option. But none of these seems to work.
But when I run tsc -w somefile.ts, its working.
Need: I want to enable compileOnSave and watch mode.