fix(transformer): convert enum numbers to strings in template literals

[Copilot]

• Explore repository structure and understand the issue
• Identify the bug in enum.rs (lines 430-434) - missing number-to-string conversion in template literals
• Create test case for enum template literal with numbers
• Fix the bug by converting numbers to strings in template literal evaluation
• Verify the fix with manual testing (regular numbers, mixed types, negative numbers, floats, Infinity, NaN)
• Run unit tests - all passing
• Run code review - reviewed, minor comment about exhaustiveness (already handled)
• Run security check - no issues found
• Update transform conformance snapshots per CI feedback
• Task completed

Summary

Fixed a bug where numeric enum values in TypeScript were not converted to strings when used in template literals. The fix converts ConstantValue::Number to strings using to_js_string() method, matching how binary addition already handles number-to-string conversion for template literals.

Updated the transform conformance snapshot to include the new test case.

Security Summary

No security vulnerabilities were found in the changes.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>transformer: computed enum with number in string template is incorrect</issue_title>
<issue_description>playground
Original report: vitejs/rolldown-vite#472

Input

export enum NumberEnum {
  NUM_1 = 1000,
  NUM_2 = 2000,
  NUM_3 = 3000,
  NUM_4 = 4000,
}

export enum ComputedEnum {
  COMPUTED_1 = `${NumberEnum.NUM_1}-${NumberEnum.NUM_2}`,
  COMPUTED_2 = `${NumberEnum.NUM_3}-${NumberEnum.NUM_4}`,
}

console.log(Object.values(ComputedEnum));

Actual

export let NumberEnum = /* @__PURE__ */ function(NumberEnum) {
	NumberEnum[NumberEnum["NUM_1"] = 1e3] = "NUM_1";
	NumberEnum[NumberEnum["NUM_2"] = 2e3] = "NUM_2";
	NumberEnum[NumberEnum["NUM_3"] = 3e3] = "NUM_3";
	NumberEnum[NumberEnum["NUM_4"] = 4e3] = "NUM_4";
	return NumberEnum;
}({});
export let ComputedEnum = /* @__PURE__ */ function(ComputedEnum) {
	ComputedEnum["COMPUTED_1"] = "-";
	ComputedEnum["COMPUTED_2"] = "-";
	return ComputedEnum;
}({});
console.log(Object.values(ComputedEnum));

Expected

export let NumberEnum = /* @__PURE__ */ function(NumberEnum) {
	NumberEnum[NumberEnum["NUM_1"] = 1e3] = "NUM_1";
	NumberEnum[NumberEnum["NUM_2"] = 2e3] = "NUM_2";
	NumberEnum[NumberEnum["NUM_3"] = 3e3] = "NUM_3";
	NumberEnum[NumberEnum["NUM_4"] = 4e3] = "NUM_4";
	return NumberEnum;
}({});
export let ComputedEnum = /* @__PURE__ */ function(ComputedEnum) {
	ComputedEnum["COMPUTED_1"] = "1000-2000";
	ComputedEnum["COMPUTED_2"] = "3000-4000";
	return ComputedEnum;
}({});
console.log(Object.values(ComputedEnum));

</issue_description>

<agent_instructions>We should take a look at ./crates/oxc_transformer/src/typescript/enum.rs to check if there is a bug</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes transformer: computed enum with number in string template is incorrect #15182

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[codspeed-hq]

CodSpeed Performance Report

Merging #15183 will not alter performance

_{Comparing copilot/fix-computed-enum-issue (6f83696) with main (cdd8e2f)}

Summary

✅ 33 untouched
⏩ 4 skipped¹

Footnotes

1. 4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Dunqing]

@copilot CI job fails, the reason is that you have to update the coverage snapshots

[Copilot]

@copilot CI job fails, the reason is that you have to update the coverage snapshots

Updated the transform conformance snapshot in commit 6f83696.