JavaScript · Junior · Question 24 of 75

What does `[1, 2, 3, 4].reduce((sum, x) => sum + x, 0)` return?

✓Correct answer: 10
2[1, 3, 6, 10]
30

Explanation

reduce walks the array, passing the accumulator from step to step; the second argument is the initial value. Without it, the first element becomes the initial accumulator, and an empty array throws a TypeError.

What does `[1, 2, 3, 4].reduce((sum, x) => sum + x, 0)` return?

Explanation

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What does [1, 2, 3, 4].reduce((sum, x) => sum + x, 0) return?

Explanation

Further reading

Test yourself

What does `[1, 2, 3, 4].reduce((sum, x) => sum + x, 0)` return?