wip: ban-dom-globals

Fixes: #181

packages/mimir/recommended.yaml

@@ -2,6 +2,7 @@
 rules:
   await-async-result: error
   await-only-promise: error
+  ban-dom-globals: error
   generator-require-yield: error
   new-parens: error
   no-case-declaration: error

packages/mimir/src/rules/ban-dom-globals.ts

@@ -0,0 +1,65 @@
+import { TypedRule, requireLibraryFile } from '@fimbul/ymir';
+import * as ts from 'typescript';
+import { getUsageDomain, UsageDomain, isSourceFile } from 'tsutils';
+import * as path from 'path';
+
+@requireLibraryFile('lib.dom.d.ts')
+export class Rule extends TypedRule {
+    public apply() {
+        for (const node of this.context.getFlatAst()) {
+            if (node.kind !== ts.SyntaxKind.Identifier)
+                continue;
+            const text = (<ts.Identifier>node).text;
+            if (isWhitelisted(text) || (getUsageDomain(<ts.Identifier>node)! & UsageDomain.Value) === 0)
+                continue;
+            const symbol = this.checker.getSymbolAtLocation(node);
+            if (
+                symbol !== undefined &&
+                symbol.valueDeclaration !== undefined &&
+                symbol.flags & (ts.SymbolFlags.Variable | ts.SymbolFlags.Function) &&
+                isDeclarationInLibDom(symbol.valueDeclaration)
+            )
+                this.addFailureAtNode(
+                    node,
+                    `Referencing global '${text}' is not allowed. Did you mean to use a local variable or parameter with a similar name?`,
+                );
+        }
+    }
+}
+
+function isDeclarationInLibDom(node: ts.Node): boolean {
+    if (node.kind === ts.SyntaxKind.FunctionDeclaration) {
+        node = node.parent!;
+    } else if (node.kind === ts.SyntaxKind.VariableDeclaration) {
+        node = node.parent!.parent!;
+        if (node.kind !== ts.SyntaxKind.VariableStatement)
+            return false;
+        node = node.parent!;
+    } else {
+        return false;
+    }
+    return isSourceFile(node) && path.basename(node.fileName) === 'lib.dom.d.ts';
+}
+
+function isWhitelisted(name: string): boolean {
+    // exclude all identifiers that start with an uppercase letter to allow `new Event()` and stuff
+    if (name.charAt(0) === name.charAt(0).toUpperCase())
+        return true;
+    switch (name) {
+        case 'document':
+        case 'window':
+        case 'navigator':
+        case 'alert':
+        case 'confirm':
+        case 'prompt':
+        case 'atob':
+        case 'btoa':
+        case 'console':
+        case 'sessionStorage':
+        case 'localStorage':
+        case 'indexedDB':
+            return true;
+        default:
+            return /^(?:(?:set|clear)(?:Timeout|Interval|Immediate)|(?:request|cancel)AnimationFrame)$/.test(name);
+    }
+}