4 ms·

Wondering how .flat() compares. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat https://developer.mozilla.org/en-US/

• _bxg1 7y ago
  .flat() should be much better, because it "knows" it's flattening. In the author's case, each individual step was treated as stateless, so a new array had to be created each time. In a .flat() function, you could have a single persistent, stateful destination array that everything gets copied into. It would be equivalent to the performance of using push(). Actually, it would probably be faster, because flat() is presumably implemented in native code instead of JS.