Reduce production bundles while preserving host registration

test/build/terserConfig.unit.spec.ts

@@ -0,0 +1,58 @@
+import { runInNewContext } from "node:vm";
+import { describe, expect, it } from "vitest";
+import { minify } from "terser";
+import { terserOption } from "../../terser.config.mjs";
+
+const fixture = `
+    const host = require("obsidian");
+    class ModuleLog {
+        constructor(configuration) { this.savedSettings = configuration; }
+        read(longParameterName) {
+            const longIntermediateValue = host.prefix + longParameterName;
+            return { savedSettings: this.savedSettings, message: longIntermediateValue };
+        }
+    }
+    function renderMessage(inputValue) { return new ModuleLog({ persistedField: "unchanged" }).read(inputValue); }
+    function readWithEval(longEvalParameter) { return eval("longEvalParameter"); }
+    function failWithName() { throw new Error("fixture failure"); }
+    module.exports = { ModuleLog, renderMessage, readWithEval, failWithName };
+`;
+
+describe("production minifier", () => {
+    it("shortens local identifiers while preserving host properties, module names, and diagnostics", async () => {
+        const result = await minify(fixture, { ...terserOption, sourceMap: false });
+        expect(result.code).toBeDefined();
+        const sandbox = {
+            module: {
+                exports: {} as {
+                    ModuleLog: { name: string };
+                    renderMessage(input: string): unknown;
+                    readWithEval(input: string): string;
+                    failWithName(): never;
+                },
+            },
+            require: (name: string) => {
+                expect(name).toBe("obsidian");
+                return { prefix: "host:" };
+            },
+        };
+        runInNewContext(result.code!, sandbox);
+        const api = sandbox.module.exports;
+        expect(api.ModuleLog.name).toBe("ModuleLog");
+        expect(api.renderMessage.name).toBe("renderMessage");
+        expect(api.renderMessage("sample")).toEqual({
+            savedSettings: { persistedField: "unchanged" },
+            message: "host:sample",
+        });
+        expect(api.readWithEval("evaluated")).toBe("evaluated");
+        let failure: Error | undefined;
+        try {
+            api.failWithName();
+        } catch (error) {
+            failure = error as Error;
+        }
+        expect(failure?.stack).toContain("failWithName");
+        expect(result.code).not.toContain("longParameterName");
+        expect(result.code).not.toContain("longIntermediateValue");
+    });
+});