This code will generate a task.json file from your Gruntfile.js and will allow you to run grunt tasks from inside VSCode

gt.js

/*  ****************************************************************************
    This code will generate a task.json file from your Gruntfile.js and will
    allow you to run grunt tasks from inside VSCode
    ****************************************************************************

    1) Put this file in the same directory of your gruntfile.js (NOTE: must be
    the app root directory) run the following command line:

        node gt.js

    The '.settings/task.json' file will be generated.

    2) Goto VSCode press Ctrl+Shift+P and type:

        Run Tasks

    select it and press Enter.

    This will list all available tasks from your Gruntfile.

    TIP: You can execute this file always you update your Gruntfile.js

    ************************************************************************* */

var path = require('path');
var fs = require('fs');

var mkdirSync = function (path) {
  try {
    fs.mkdirSync(path);
  } catch(e) {
    if ( e.code != 'EEXIST' ) throw e;
  }
}

function getAllTasks(gruntFilePath) {
    var data = fs.readFileSync(gruntFilePath);
    var str = data.toString();
    var regx = /grunt[|\n|\r|\s|\t]*\.[|\n|\r|\s|\t]*registerTask\([|\n|\r|\s|\t]*['|"]([a-zA-Z0-9:_-]+)['|"]/igm;
    var match = null;
    var result = [];
    while (match = regx.exec(str)) {
        result.push(match[1]);
    }
    return result;
}

var file = './Gruntfile.js';

if (fs.existsSync(file)) {
    var task = {
        version: "0.1.0",
        command: "grunt",
        isShellCommand: true,
        args: [],
        tasks: []
    };

    var gruntTasks = getAllTasks(file);

    gruntTasks.forEach(function (gt) {
        task.tasks.push({
            taskName: gt,
            args: [],
            isBuildCommand: true,
            problemMatcher: []
        });
    });

    mkdirSync('.settings');

    var generate = function() {
        var taskJson = JSON.stringify(task, null, 4);
        fs.writeFile(".settings/tasks.json", taskJson, function(err) {
            if(err) {
                console.log(err);
            } else {
                console.log("The file was .settings/tasks.json saved!");
            }
        });
    }

    if(!fs.existsSync('.settings/tasks.json')) {
        generate();
    } else {
        if(process.argv[2] != '--force') {
            console.log('\033[31mThere is already a file named .settings/tasks.json. Use --fore to overwrite this file.\033[0m')
        } else {
            generate();
        }
    }
} else {
    console.log('\033[31mGruntfile.js not found\033[0m');
    process.exit(1);
}