Code RoomUnnecessary spread in array merge
HardPrep Room Coding #1722

Unnecessary spread in array merge

Code reviewCode quality & reviewSenior–Staff~25 min

Review this JavaScript reducer that merges event batches.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 25 min
Mark a line and say what kind of problem it is.0 findings
1function mergeBatches(batches) {
2 // batches: array of arrays of events
3 return batches.reduce((acc, batch) => {
4 return [...acc, ...batch];
5 }, []);
6}
7 
8function groupByType(events) {
9 return events.reduce((acc, e) => {
10 return { ...acc, [e.type]: [...(acc[e.type] || []), e] };
11 }, {});
12}
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.