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Array FlatMap
FlatMap is a single method which can be usable for flat and map methods.
As you know
flat(), flattening the 1-level deep and map() to loop into an array.If we include both, we called
flatMap() 😉 So, instead if calling two methods
flat() and map(), you can use single method called flatMap().let plants = ['💐', '🌲', '🌻', '🌹'];
// ❌ map + flat
plants.map(plant => [plant, '🍁']).flat();
// Output
//["💐", "🍁", "🌲", "🍁", "🌻", "🍁", "🌹", "🍁"]
// ✅ flatMap
plants.flatMap(plant => [plant, "🍁"])
// Output
// ["💐", "🍁", "🌲", "🍁", "🌻", "🍁", "🌹", "🍁"]📝 FlatMap() always do first map() and then it flat().
In
flat(), we use to pass arguments where you set the depth, arguments define how deep a nested array should be flattened.let plants = [[["🌻", "🌹"]]];
plants.flat(2);
// ["🌻", "🌹"]let plants = [[["🌻", "🌹"]]];
plants.flatMap(plant => [plant]);
// [["🌻", "🌹"]]Yes, You can also do filter here using
flatMap().let arr = [5, 4, -3, 20, -4, 18]
arr.flatMap(i => {
return i < 0 ? [] : [i];
})
// [5, 4, 20, 18]flatMap() method always helps if you want to use map and flat methods both together.Thanks for reading the article ❤️
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