If I were to implement something like filterMap, I would pass in the predicate and the transformation as separate functions. However, you can use reduce for what you're doing, no need to implement a new method on Array.
filterMap
reduce
Array
const emails = customers.reduce( (prev, c) => c.active ? [ ...prev, c ] : prev, [] )
It is 80% slower, jsperf.com/array-filtermap/2
Yeah, sorry, been using array destructuring too much lately. If it's speed we're going after we can't create a new array at each iteration step.
const emails = customers.reduce( (prev, c) => { if (c.active) prev.push(c) return prev }, [] )
This way reduce can be used as map as well, nice trick but I still prefer filterMap for its smaller syntax.
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If I were to implement something like
filterMap, I would pass in the predicate and the transformation as separate functions. However, you can usereducefor what you're doing, no need to implement a new method onArray.It is 80% slower, jsperf.com/array-filtermap/2
Yeah, sorry, been using array destructuring too much lately. If it's speed we're going after we can't create a new array at each iteration step.
This way reduce can be used as map as well, nice trick but I still prefer filterMap for its smaller syntax.