Ember component what is layout and how to write the functions?

I created a component, it gives the output as :

import Ember from 'ember';
import layout from '../templates/components/sample-work';

export default Ember.Component.extend({
  layout
});

When i try to add some init method like :

import Ember from 'ember';
import layout from '../templates/components/sample-work';

export default Ember.Component.extend({
  layout,
  init(){
    alert.log('hi');
  }
});

My component not at all called. what is the issue here? what is the correct way to handle the component here?