Code reviewHardcr-g086

Subject Unnecessary allocationLevel Senior–Staff~25 minCommon in Code quality & review interviewsIndustries Software development

Question

Review this JavaScript reducer that merges event batches.

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Code to reviewjavascript

1function mergeBatches(batches) {2  // batches: array of arrays of events3  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}

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