JavaScript · Junior · Question 73 of 75

What does `[1, [2, [3]]].flat()` return?

✓Correct answer: [1, 2, [3]]
2[1, 2, 3]
3[[1, 2, 3]]

Explanation

By default flat flattens one level. Pass a depth (flat(2)) or Infinity to flatten completely. flatMap maps then flattens one level.

Further reading

MDN: Array.prototype.flat() ↗

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