In the tsconfig.json set

"sourceMap": true,

to generate mappings alongside with js-files from the TypeScript sources using the tsc command. The launch.json file:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Launch Program",
            "program": "${workspaceRoot}\\\\index.js",
            "cwd": "${workspaceRoot}",
            "outFiles": [],
            "sourceMaps": true
        }
    ]
}

This starts node with the generated index.js (if your main file is index.ts) file and the debugger in Visual Studio Code which halts on breakpoints and resolves variable values within your TypeScript code.