3 ms·
if you are using slice(0,5) then all the extra objects you mapped are lost and you have no reference to them.
by darepublic 5y ago
if you are using slice(0,5) then all the extra objects you mapped are lost and you have no reference to them.
- brundolf 5y agoNot true. slice() clones-and-drops the array, but not the objects inside.
- darepublic 5y agobut map also creates a new array, and within map you are not mutating the items of the old array but creating brand new ones no? [...].map(p => ({...p, canDrink})) ^ the original items of the array are not mutated in this map callback. you could mutate them if you really wanted, i.e. [...].map(p => {p.canDrink = p.age > 20; return p}) but that is a straight up hack.