JavaScript · Junior · Question 54 of 75

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

✓Correct answer: 3 - the new length of the array
2[1, 2, 3]
3undefined

Explanation

push mutates the array and returns its new length, a common source of bugs like arr = arr.push(x). For an immutable version use [...arr, x].

Further reading

javascript.info: Array methods ↗

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