const shallowEqual = < T > ( a , b ) => { if ( a === b ) return true ; if ( ! a || ! b ) return false ; const len = a . length ; if ( b . length !== len ) { return false ; } for ( let i = 0 ; i < len ; i += 1 ) { if ( a [ i ] !== b [ i ] ) return false ; } return true ; } ; export default shallowEqual ;