import { Mutator } from './Mutator' ; import { assert } from 'chai' ; describe ( 'Mutator' , function ( ) { it ( "Test mutation" , function ( ) { let name = { first : 'Alice' , last : 'Smith' } ; name = Mutator . mutate ( name , ( current ) => { current . first = 'Bob' ; return current ; } ) ; assert . equal ( name . first , 'Bob' ) ; } ) ; } ) ; interface Name { first : string ; last : string ; }