while running your angular 2 scripts, you noticed a warning message on your console that says:
Angular is running in the development mode. Call enableProdMode() to enable the production mode

so where do you put enableProdMode()?

usually you would put this code in your main.ts file just before calling bootstrap
import {enableProdMode,exampleComponent} from '@angular/core';

// ADD enableProdMode(); BEFORE BOOTSTRAP
.bootstrapModule( AppModule);

after you add this code, you will not see the message anymore.

hope that helps