import { compose } from './compose' ; describe ( 'compose' , ( ) => { it ( 'composes' , ( ) => { const fn1 = compose ( ( arg ) => arg + 1 ) ; expect ( fn1 ( 1 ) ) . toBe ( 2 ) ; const fn2 = compose ( ( arg ) => arg + 1 , ( arg ) => arg * 2 ) ; expect ( fn2 ( 1 ) ) . toBe ( 3 ) ; } ) ; } ) ;