export function shallowEqual ( a , b ) { for ( const key in a ) { if ( { } . hasOwnProperty . call ( a , key ) && ( ! { } . hasOwnProperty . call ( b , key ) || a [ key ] !== b [ key ] ) ) { return false ; } } for ( const key in b ) { if ( { } . hasOwnProperty . call ( b , key ) && ! { } . hasOwnProperty . call ( a , key ) ) { return false ; } } return true ; }