Debugging info is enabled by default during development in Angular2.

Debugging tools need to be enabled with enableDebugTools

For production enableProdMode() should be called to get rid of debug information that slows down your application and increases code size.

For details how to access debug info from the console see how to access Angular2 component specific data in console?

https://augury.angular.io/ provides a browser Plugin with a graphical UI

Because an Angular application is built for deployment, the options need to be enabled when the application is built, otherwise it won't be included in the deployable.

Tested with Angular 5 / CLI 1.5.5

1. Install the Chrome Debugger Extension
2. Create the launch.json (inside .vscode folder)
3. Use my launch.json (see below)
4. Create the tasks.json (inside .vscode folder)
5. Use my tasks.json (see below)
6. Press CTRL+SHIFT+B
7. Press F5

launch.json for angular/cli >= 1.3

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Launch Chrome",
      "type": "chrome",
      "request": "launch",
      "url": "http://localhost:4200/#",
      "webRoot": "${workspaceFolder}"
    },
    {
      "name": "Attach Chrome",
      "type": "chrome",
      "request": "attach",
      "url": "http://localhost:4200/#",
      "webRoot": "${workspaceFolder}"
    },
    {
      "name": "Launch Chrome (Test)",
      "type": "chrome",
      "request": "launch",
      "url": "http://localhost:9876/debug.html",
      "webRoot": "${workspaceFolder}"
    },
    {
      "name": "Launch Chrome (E2E)",
      "type": "node",
      "request": "launch",
      "program": "${workspaceFolder}/node_modules/protractor/bin/protractor",
      "protocol": "inspector",
      "args": ["${workspaceFolder}/protractor.conf.js"]
    }
  ]
}

tasks.json for angular/cli >= 1.3

{
    "version": "2.0.0",
    "tasks": [
      {
        "identifier": "ng serve",
        "type": "npm",
        "script": "start",
        "problemMatcher": [],
        "group": {
          "kind": "build",
          "isDefault": true
        }
      },
      {
        "identifier": "ng test",
        "type": "npm",
        "script": "test",
        "problemMatcher": [],
        "group": {
          "kind": "test",
          "isDefault": true
        }
      }
    ]
  }

Tested with Angular 2.4.8

1. Install the Chrome Debugger Extension
2. Create the launch.json
3. Use my launch.json (see below)
4. Start the NG Live Development Server (ng serve)
5. Press F5

launch.json for angular/cli >= 1.0.0-beta.32

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "chrome",
      "request": "launch",
      "name": "Launch Chrome",
      "url": "http://localhost:4200",
      "webRoot": "${workspaceFolder}",
      "sourceMaps": true,
      "userDataDir": "${workspaceFolder}/.vscode/chrome",
      "runtimeArgs": [
        "--disable-session-crashed-bubble"
      ]
    },
    {
      "name": "Attach Chrome",
      "type": "chrome",
      "request": "attach",
      "url": "http://localhost:4200",
      "port": 9222,
      "webRoot": "${workspaceFolder}",
      "sourceMaps": true
    }
  ]
}

launch.json for angular/cli < 1.0.0-beta.32

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Lunch Chrome",
      "type": "chrome",
      "request": "launch",
      "url": "http://localhost:4200",
      "webRoot": "${workspaceFolder}/src/app",
      "sourceMaps": true,
      "sourceMapPathOverrides": {
        "webpack:///./~/*": "${workspaceFolder}/node_modules/*",
        "webpack:///./src/*": "${workspaceFolder}/src/*"
      },
      "userDataDir": "${workspaceFolder}/.vscode/chrome",
      "runtimeArgs": [
        "--disable-session-crashed-bubble"
      ]
    },
    {
      "name": "Attach Chrome",
      "type": "chrome",
      "request": "attach",
      "url": "http://localhost:4200",
      "port": 9222,
      "webRoot": "${workspaceFolder}/src/app",
      "sourceMaps": true,
      "sourceMapPathOverrides": {
        "webpack:///./~/*": "${workspaceFolder}/node_modules/*",
        "webpack:///./src/*": "${workspaceFolder}/src/*"
      }
    }
  ]
}

$logProvider.debugEnabled(true)

This is only available in AngularJS 1.1.2 or later.

https://github.com/angular/angular.js/pull/1625

Here is an example of it being set.

var app = angular.module('plunker', []);

app.config(function($logProvider){
  $logProvider.debugEnabled(true);
});

app.controller('MainCtrl', function($scope, $log ) {
  $scope.name = 'World';
  $scope.model = {value: "test"};
  $log.debug('TEST Log');
});

http://plnkr.co/edit/HZCAoS?p=preview

By default it is on.