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⚡ Bolt: O(n) calculation optimization in Dashboard #150

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⚡ Bolt: O(n) calculation optimization in Dashboard #150

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14 changes: 8 additions & 6 deletions frontend/dashboard.js
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Original file line number Diff line number Diff line change
Expand Up @@ -130,19 +130,21 @@ function updateStatistics(subjects) {
return;
}

const scores = subjects.map(subject => subject.scoreValue);
const highest = Math.max(...scores);

// 計算加權平均
// 計算最高分與加權平均，合併迴圈以減少陣列分配與迭代，並避免 Math.max 展開大陣列時可能發生的 Stack Overflow
let highest = -Infinity;
let totalWeightedScore = 0;
let totalWeight = 0;

subjects.forEach(subject => {
for (let i = 0; i < subjects.length; i++) {
const subject = subjects[i];
const score = subject.scoreValue;

if (score > highest) highest = score;

const weight = getSubjectWeight(subject.SubjectName);
totalWeightedScore += score * weight;
totalWeight += weight;
});
}
Comment on lines +138 to +147

@gemini-code-assist gemini-code-assist Bot Apr 7, 2026

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medium

Using a for...of loop would improve readability while maintaining the performance benefits of a single pass. Additionally, replacing the if condition with highest = Math.max(highest, score) is more idiomatic and ensures consistent NaN handling. If any scoreValue is NaN, highest will correctly become NaN, matching the behavior of weightedAvg and the original implementation (which used Math.max(...scores)).

    for (const subject of subjects) {
        const score = subject.scoreValue;
        highest = Math.max(highest, score);

        const weight = getSubjectWeight(subject.SubjectName);
        totalWeightedScore += score * weight;
        totalWeight += weight;
    }

Comment on lines +133 to +147

Copilot AI Apr 7, 2026

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scoreValue can be NaN (see getNumericScore() fallback path), and the new loop can leave highest as -Infinity when all scores are non-finite, which then renders -Infinity in the UI. Also, a single NaN score will propagate totalWeightedScore to NaN and make weightedAvg.toFixed(1) show NaN. Consider skipping non-finite scores (and their weights) when computing highest/average, and rendering '--' (or 0) when no valid numeric scores exist.

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const weightedAvg = totalWeight > 0 ? totalWeightedScore / totalWeight : 0;

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