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Get Started Free →Use when auditing slow page loads, heavy assets, or rendering delays related to Remove duplicate JavaScript libraries. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
.claude/skills/thedaviddias-duplicate-js/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-01 | ✗→✓ | ▲ Improved | -8% | 0% |
| case-04 | ✗→✓ | ▲ Improved | -1% | 0% |
| case-06 | ✗→✓ | ▲ Improved | 7% | 0% |
| case-09 | ✗→✓ | ▲ Improved | 10% | 0% |
| case-10 | ✗→✓ | ▲ Improved | 7% | 0% |
Duplicate libraries increase bundle size and memory usage, and can lead to unexpected behavior or conflicts between different versions of the same code.
Identify duplicate JavaScript libraries or multiple versions of the same library being loaded using Lighthouse or bundle analysis tools.
Consolidate dependencies to use a single version and ensure third-party scripts don't bring in redundant libraries.
Explain the risks of loading duplicate JavaScript libraries and how it impacts performance and stability.
Review the routes, assets, and loading behavior that affect Remove duplicate JavaScript libraries. Flag exact files, requests, or rendering steps that add unnecessary network, CPU, or layout cost, and describe the measurement method used to confirm the issue.
For full implementation details, code examples, and framework-specific guidance, see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/performance/duplicate-js
| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-02 | pass→pass | 17,390 | 15,156 | -13% | 1 | 1 | 0% | 3,625 | 3,623 | -0% | 0 | 0 | — |
case-01 | fail→pass | 12,607 | 10,395 | -18% | 1 | 1 | 0% | 2,454 | 2,266 | -8% | 0 | 0 | — |
case-03 | pass→pass | 12,170 | 9,426 | -23% | 1 | 1 | 0% | 2,286 | 2,084 | -9% | 0 | 0 | — |
case-04 | fail→pass | 10,493 | 9,354 | -11% | 1 | 1 | 0% | 2,171 | 2,148 | -1% | 0 | 0 | — |
case-05 | pass→pass | 11,930 | 10,986 | -8% | 1 | 1 | 0% | 2,268 | 2,297 | +1% | 0 | 0 | — |
case-06 | fail→pass | 11,555 | 11,532 | -0% | 1 | 1 | 0% | 2,472 | 2,647 | +7% | 0 | 0 | — |
case-07 | pass→pass | 15,301 | 11,794 | -23% | 1 | 1 | 0% | 2,479 | 2,323 | -6% | 0 | 0 | — |
case-08 | pass→pass | 15,009 | 13,872 | -8% | 1 | 1 | 0% | 2,775 | 2,731 | -2% | 0 | 0 | — |
case-09 | fail→pass | 11,350 | 11,993 | +6% | 1 | 1 | 0% | 2,337 | 2,561 | +10% | 0 | 0 | — |
case-10 | fail→pass | 15,561 | 13,874 | -11% | 1 | 1 | 0% | 2,712 | 2,907 | +7% | 0 | 0 | — |
case-11 | pass→pass | 14,176 | 11,722 | -17% | 1 | 1 | 0% | 2,297 | 2,094 | -9% | 0 | 0 | — |
case-12 | pass→pass | 12,770 | 12,483 | -2% | 1 | 1 | 0% | 2,286 | 2,581 | +13% | 0 | 0 | — |
case-13 | pass→pass | 13,057 | 11,269 | -14% | 1 | 1 | 0% | 2,175 | 2,349 | +8% | 0 | 0 | — |
case-14 | pass→pass | 11,588 | 10,311 | -11% | 1 | 1 | 0% | 2,045 | 2,163 | +6% | 0 | 0 | — |
case-15 | pass→pass | 13,636 | 11,494 | -16% | 1 | 1 | 0% | 2,436 | 2,211 | -9% | 0 | 0 | — |
case-16 | fail→fail | 12,501 | 10,469 | -16% | 1 | 1 | 0% | 2,120 | 1,938 | -9% | 0 | 0 | — |
case-17 | pass→pass | 15,442 | 12,185 | -21% | 1 | 1 | 0% | 2,954 | 2,582 | -13% | 0 | 0 | — |
case-18 | pass→fail | 16,350 | 14,018 | -14% | 1 | 1 | 0% | 2,519 | 2,584 | +3% | 0 | 0 | — |
case-19 | fail→pass | 11,861 | 4,951 | -58% | 1 | 1 | 0% | 1,944 | 1,308 | -33% | 0 | 0 | — |
case-20 | pass→fail | 18,571 | 14,036 | -24% | 1 | 1 | 0% | 3,102 | 2,738 | -12% | 0 | 0 | — |
case-21 | pass→pass | 15,739 | 14,437 | -8% | 1 | 1 | 0% | 2,562 | 2,697 | +5% | 0 | 0 | — |
case-22 | pass→pass | 15,587 | 13,796 | -11% | 1 | 1 | 0% | 2,357 | 2,332 | -1% | 0 | 0 | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 22 cases were attempted. The headline lift of +18 percentage points is the difference between those two pass rates over the 22 comparable cases. 2 cases got worse with the skill loaded, and they are included in that figure.
Without the skill loaded, the model failed this case. With it loaded, the same prompt on the same model passed. This is one improved case from the latest verified run; every case, including any that regressed, is in the table above.
Other measured skills in the registry, with their headline benchmark lift.