fix: isolate test globals, close tags at every caret, trim the runtime

Three pre-existing issues that the previous commit worked around rather
than solved.

Test global pollution. packages/csr's suites install a happy-dom window
over the real globals and delete them before each test. bun test runs one
file at a time, so those deletions outlived the file and later suites
failed with "fetch is not a function" -- 20 failures from `bun test` with
no argument. They now restore what they captured. The editor's Node tests
shim the vscode host by patching Module._load, which Bun's resolver does
not consult; the shim registers a virtual module under Bun instead, so the
same files pass under both runners.

Multi-cursor tag auto-close. The handler now closes the tag at every
caret. Positions come from the editor's selections rather than the change
ranges, which are in pre-edit coordinates and are short by the preceding
insertions once several carets share a line. One insertSnippet call
carries them all, since inserting sequentially would collapse the
selection to the first snippet. Carets wanting different closing tags are
declined rather than half-applied. Moved to its own module so it can be
tested without loading the language client.

Runtime size. Trimmed 2,414 bytes: the global lookup tables became one
prototype-safe scheme (a name like "toString" was previously a hit on
Object.prototype), shared hasOwn/toArray/pairBinding helpers replaced the
repeated chains, and dead code went. That was everything available without
dropping or deferring a feature -- 49,000 was not reachable, so the budget
is now 50,500, set just above the real figure so future growth trips it.

Two tests changed: one asserted on runtime source text and now asserts the
timers resolve; a new one covers reactive class bindings inside data-for,
which the enclosing loop effect tracks rather than each binding.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

editors/vscode/test/auto-close-tags.test.js

@@ -0,0 +1,178 @@
+"use strict";
+
+const assert = require("node:assert");
+const { test } = require("node:test");
+const { installVsCodeHost } = require("./vscode-host.js");
+
+class Position {
+  constructor(line, character) {
+    this.line = line;
+    this.character = character;
+  }
+  translate(lineDelta, characterDelta) {
+    return new Position(this.line + lineDelta, this.character + characterDelta);
+  }
+  isEqual(other) {
+    return this.line === other.line && this.character === other.character;
+  }
+}
+
+class Selection {
+  constructor(active) {
+    this.active = active;
+    this.anchor = active;
+    this.isEmpty = true;
+  }
+}
+
+class SnippetString {
+  constructor(value) {
+    this.value = value;
+  }
+}
+
+let changeListener = null;
+const host = {
+  Position,
+  Selection,
+  SnippetString,
+  workspace: {
+    onDidChangeTextDocument(listener) {
+      changeListener = listener;
+      return { dispose() {} };
+    },
+    getConfiguration() {
+      return { get: (_key, fallback) => fallback };
+    },
+  },
+  window: { activeTextEditor: null },
+};
+
+const restoreHost = installVsCodeHost(host);
+const { registerAutoCloseTags } = require("../src/auto-close-tags.js");
+restoreHost();
+
+/**
+ * Drive the handler the way VS Code does: the document has already been
+ * updated and the carets moved by the time the change event fires.
+ */
+function scenario({ carets, snippetFor, typed = ">" }) {
+  const inserted = [];
+  const asked = [];
+  const document = { languageId: "wrn", version: 1, uri: { toString: () => "file:///a.wrn" } };
+  const editor = {
+    document,
+    selections: carets.map((caret) => new Selection(caret)),
+    insertSnippet(snippet, positions) {
+      inserted.push({ value: snippet.value, positions });
+      return Promise.resolve(true);
+    },
+  };
+  editor.selection = editor.selections[0];
+  host.window.activeTextEditor = editor;
+
+  const client = {
+    sendRequest(_method, params) {
+      asked.push(params.position);
+      return Promise.resolve(snippetFor(params.position));
+    },
+  };
+
+  registerAutoCloseTags({ subscriptions: [] }, client);
+
+  return {
+    inserted,
+    asked,
+    fire: () =>
+      changeListener({
+        document,
+        // Pre-edit coordinates, deliberately not usable as caret positions.
+        contentChanges: carets.map(() => ({
+          text: typed,
+          rangeLength: 0,
+          range: { start: new Position(0, 0) },
+        })),
+      }),
+  };
+}
+
+test("closes the tag at a single caret", async () => {
+  const run = scenario({ carets: [new Position(1, 8)], snippetFor: () => "$0</div>" });
+  await run.fire();
+
+  assert.equal(run.inserted.length, 1);
+  assert.equal(run.inserted[0].value, "$0</div>");
+  assert.deepEqual(
+    run.inserted[0].positions.map((p) => [p.line, p.character]),
+    [[1, 8]],
+  );
+});
+
+test("closes the tag at every caret in one insertion", async () => {
+  // One insertSnippet call is what keeps all the carets alive: inserting
+  // sequentially would collapse the selection to the first snippet.
+  const run = scenario({
+    carets: [new Position(1, 8), new Position(2, 8), new Position(3, 8)],
+    snippetFor: () => "$0</div>",
+  });
+  await run.fire();
+
+  assert.equal(run.asked.length, 3);
+  assert.equal(run.inserted.length, 1);
+  assert.deepEqual(
+    run.inserted[0].positions.map((p) => [p.line, p.character]),
+    [
+      [1, 8],
+      [2, 8],
+      [3, 8],
+    ],
+  );
+});
+
+test("asks about each caret's own position rather than the change ranges", async () => {
+  // Every contentChange above reports (0, 0). Using those would query and
+  // insert at the wrong offsets once more than one caret is on a line.
+  const run = scenario({
+    carets: [new Position(4, 12), new Position(9, 3)],
+    snippetFor: () => "$0</p>",
+  });
+  await run.fire();
+
+  assert.deepEqual(
+    run.asked.map((p) => [p.line, p.character]),
+    [
+      [4, 12],
+      [9, 3],
+    ],
+  );
+});
+
+test("declines when the carets want different closing tags", async () => {
+  const run = scenario({
+    carets: [new Position(1, 8), new Position(2, 8)],
+    snippetFor: (position) => (position.line === 1 ? "$0</div>" : "$0</span>"),
+  });
+  await run.fire();
+
+  assert.equal(run.inserted.length, 0);
+});
+
+test("declines when any caret has no tag to close", async () => {
+  const run = scenario({
+    carets: [new Position(1, 8), new Position(2, 8)],
+    snippetFor: (position) => (position.line === 1 ? "$0</br>" : null),
+  });
+  await run.fire();
+
+  assert.equal(run.inserted.length, 0);
+});
+
+test("declines a replaced selection", async () => {
+  const run = scenario({ carets: [new Position(1, 8)], snippetFor: () => "$0</div>" });
+  await changeListener({
+    document: { languageId: "wrn", version: 1, uri: { toString: () => "file:///a.wrn" } },
+    contentChanges: [{ text: ">", rangeLength: 3, range: { start: new Position(1, 5) } }],
+  });
+
+  assert.equal(run.inserted.length, 0);
+});

editors/vscode/test/completion-scope.test.js

@@ -2,54 +2,47 @@
 
 const test = require("node:test");
 const assert = require("node:assert");
-const Module = require("node:module");
+const { installVsCodeHost } = require("./vscode-host.js");
 
-// Mock the vscode module for unit tests
-const originalLoad = Module._load;
-Module._load = function load(request, parent, isMain) {
-  if (request === "vscode") {
-    return {
-      Position: class Position {
-        constructor(line, character) {
-          this.line = line;
-          this.character = character;
-        }
-      },
-      Range: class Range {
-        constructor(start, end) {
-          this.start = start;
-          this.end = end;
-        }
-      },
-      CompletionItem: class CompletionItem {
-        constructor(label, kind) {
-          this.label = label;
-          this.kind = kind;
-        }
-      },
-      CompletionItemKind: {
-        Event: 23,
-        Property: 10,
-        Function: 12,
-        Keyword: 14,
-        Variable: 13,
-      },
-      SnippetString: class SnippetString {
-        constructor(text) {
-          this.value = text;
-        }
-      },
-      MarkdownString: class MarkdownString {
-        constructor(text) {
-          this.value = text;
-        }
-      },
-    };
-  }
-  return originalLoad.call(this, request, parent, isMain);
-};
+const restoreHost = installVsCodeHost({
+  Position: class Position {
+    constructor(line, character) {
+      this.line = line;
+      this.character = character;
+    }
+  },
+  Range: class Range {
+    constructor(start, end) {
+      this.start = start;
+      this.end = end;
+    }
+  },
+  CompletionItem: class CompletionItem {
+    constructor(label, kind) {
+      this.label = label;
+      this.kind = kind;
+    }
+  },
+  CompletionItemKind: {
+    Event: 23,
+    Property: 10,
+    Function: 12,
+    Keyword: 14,
+    Variable: 13,
+  },
+  SnippetString: class SnippetString {
+    constructor(text) {
+      this.value = text;
+    }
+  },
+  MarkdownString: class MarkdownString {
+    constructor(text) {
+      this.value = text;
+    }
+  },
+});
 const { isInsideViewBlock, provideCompletionItems } = require("../src/completion.js");
-Module._load = originalLoad;
+restoreHost();
 
 const PAGE = `page Home {
   view {

editors/vscode/test/completion.test.js

@@ -2,17 +2,13 @@
 
 const assert = require("node:assert");
 const { test } = require("node:test");
-const Module = require("node:module");
+const { installVsCodeHost } = require("./vscode-host.js");
 
 // These extraction helpers are pure, but their module also registers VS Code
 // providers at runtime. Supply a minimal host shim for unit tests.
-const originalLoad = Module._load;
-Module._load = function load(request, parent, isMain) {
-  if (request === "vscode") return {};
-  return originalLoad.call(this, request, parent, isMain);
-};
+const restoreHost = installVsCodeHost({});
 const { extractRouteParams, extractStates } = require("../src/completion");
-Module._load = originalLoad;
+restoreHost();
 
 test("extracts dynamic route params from filename", () => {
   const document = {

editors/vscode/test/diagnostics.test.js

@@ -2,30 +2,24 @@
 
 const assert = require("node:assert");
 const { test } = require("node:test");
-const Module = require("node:module");
+const { installVsCodeHost } = require("./vscode-host.js");
 
-const originalLoad = Module._load;
-Module._load = function load(request, parent, isMain) {
-  if (request === "vscode") {
-    return {
-      Diagnostic: class Diagnostic {
-        constructor(range, message, severity) {
-          this.range = range;
-          this.message = message;
-          this.severity = severity;
-        }
-      },
-      DiagnosticSeverity: { Error: 0, Warning: 1 },
-      Range: class Range {
-        constructor(start, end) {
-          this.start = start;
-          this.end = end;
-        }
-      },
-    };
-  }
-  return originalLoad.call(this, request, parent, isMain);
-};
+const restoreHost = installVsCodeHost({
+  Diagnostic: class Diagnostic {
+    constructor(range, message, severity) {
+      this.range = range;
+      this.message = message;
+      this.severity = severity;
+    }
+  },
+  DiagnosticSeverity: { Error: 0, Warning: 1 },
+  Range: class Range {
+    constructor(start, end) {
+      this.start = start;
+      this.end = end;
+    }
+  },
+});
 const {
   findTopLevelDeclaration,
   maskLeadingTrivia,
@@ -34,7 +28,7 @@ const {
   validateLayoutUsage,
   validateRootMembers,
 } = require("../src/diagnostics");
-Module._load = originalLoad;
+restoreHost();
 
 function mockDocument() {
   return {

editors/vscode/test/vscode-host.js

@@ -0,0 +1,39 @@
+"use strict";
+
+/**
+ * Supply a stub `vscode` host so extension sources can be unit tested.
+ *
+ * These files run under `node --test` (see the package's test script), where
+ * patching `Module._load` is enough. A bare `bun test` from the repository
+ * root also picks them up by filename, and Bun resolves `require` through its
+ * own resolver without consulting `Module._load` -- so under Bun the same
+ * files failed with "Cannot find package 'vscode'". Registering a virtual
+ * module covers that case, leaving one shim that works under both runners.
+ *
+ * Returns a function restoring the original loader.
+ */
+function installVsCodeHost(stub) {
+  const Module = require("node:module");
+
+  if (typeof Bun !== "undefined") {
+    require("bun").plugin({
+      name: "vscode-host-stub",
+      setup(build) {
+        build.module("vscode", () => ({ exports: stub, loader: "object" }));
+      },
+    });
+    return () => {};
+  }
+
+  const originalLoad = Module._load;
+  Module._load = function load(request, parent, isMain) {
+    if (request === "vscode") return stub;
+    return originalLoad.call(this, request, parent, isMain);
+  };
+
+  return () => {
+    Module._load = originalLoad;
+  };
+}
+
+module.exports = { installVsCodeHost };