feat: no-window (#1166)

docs/rules/no_window_global.md

@@ -0,0 +1,35 @@
+Disallows the use of the `window` object.
+
+Using the `window` global is deprecated and scheduled for removal in Deno 2.0.
+Deno does not have a window and `typeof window === "undefined"` is often used to
+tell if the code is running in the browser.
+
+### Invalid:
+
+```typescript
+const a = await window.fetch("https://deno.land");
+
+const b = window.Deno.metrics();
+console.log(window);
+
+window.addEventListener("load", () => {
+  console.log("Loaded.");
+});
+```
+
+### Valid:
+
+```typescript
+const a1 = await fetch("https://deno.land");
+const a2 = await globalThis.fetch("https://deno.land");
+const a3 = await self.fetch("https://deno.land");
+
+const b1 = Deno.metrics();
+const b2 = globalThis.Deno.metrics();
+const b3 = self.Deno.metrics();
+console.log(globalThis);
+
+addEventListener("load", () => {
+  console.log("Loaded.");
+});
+```

src/rules.rs

@@ -91,6 +91,7 @@ pub mod no_unsafe_negation;
 pub mod no_unused_labels;
 pub mod no_unused_vars;
 pub mod no_var;
+pub mod no_window;
 pub mod no_window_prefix;
 pub mod no_with;
 pub mod prefer_as_const;
@@ -312,6 +313,7 @@ fn get_all_rules_raw() -> Vec<&'static dyn LintRule> {
     &no_unused_labels::NoUnusedLabels,
     &no_unused_vars::NoUnusedVars,
     &no_var::NoVar,
+    &no_window::NoWindow,
     &no_window_prefix::NoWindowPrefix,
     &no_with::NoWith,
     &prefer_as_const::PreferAsConst,

src/rules/no_window.rs

@@ -0,0 +1,119 @@
+// Copyright 2020-2021 the Deno authors. All rights reserved. MIT license.
+use super::Context;
+use super::LintRule;
+use crate::handler::Handler;
+use crate::handler::Traverse;
+use crate::Program;
+
+use deno_ast::view as ast_view;
+use deno_ast::SourceRanged;
+use if_chain::if_chain;
+
+#[derive(Debug)]
+pub struct NoWindow;
+
+const CODE: &str = "no-window";
+const MESSAGE: &str =
+  "window is deprecated and scheduled for removal in Deno 2.0";
+const HINT: &str = "Instead, use `globalThis`";
+
+impl LintRule for NoWindow {
+  fn tags(&self) -> &'static [&'static str] {
+    &["recommended"]
+  }
+
+  fn code(&self) -> &'static str {
+    CODE
+  }
+
+  fn lint_program_with_ast_view(
+    &self,
+    context: &mut Context,
+    program: Program<'_>,
+  ) {
+    NoWindowGlobalHandler.traverse(program, context);
+  }
+
+  #[cfg(feature = "docs")]
+  fn docs(&self) -> &'static str {
+    include_str!("../../docs/rules/no_window_global.md")
+  }
+}
+
+struct NoWindowGlobalHandler;
+
+impl Handler for NoWindowGlobalHandler {
+  fn ident(&mut self, ident: &ast_view::Ident, ctx: &mut Context) {
+    if_chain! {
+      if ident.sym() == "window";
+      if ctx.scope().is_global(&ident.to_id());
+      then {
+        ctx.add_diagnostic_with_hint(
+          ident.range(),
+          CODE,
+          MESSAGE,
+          HINT,
+        );
+      }
+    }
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn no_window_valid() {
+    assert_lint_ok! {
+      NoWindow,
+      "fetch();",
+      "self.fetch();",
+      "globalThis.fetch();",
+
+      // `window` is shadowed
+      "const window = 42; window.fetch();",
+      r#"const window = 42; window["fetch"]();"#,
+      r#"const window = 42; window[`fetch`]();"#,
+      "const window = 42; window.alert();",
+      r#"const window = 42; window["alert"]();"#,
+      r#"const window = 42; window[`alert`]();"#,
+    };
+  }
+
+  #[test]
+  fn no_window_invalid() {
+    assert_lint_err! {
+      NoWindow,
+      MESSAGE,
+      HINT,
+      r#"window.fetch()"#: [
+        {
+          col: 0,
+        }
+      ],
+      r#"window["fetch"]()"#: [
+        {
+          col: 0,
+        }
+      ],
+      r#"window[`fetch`]()"#: [
+        {
+          col: 0,
+        }
+      ],
+      r#"
+function foo() {
+  const window = 42;
+  return window;
+}
+window;
+      "#: [
+        {
+          col: 0,
+          line: 6,
+        }
+      ],
+    };
+  }
+}

src/rules/no_window_prefix.rs

@@ -263,7 +263,7 @@ mod tests {
   use super::*;
 
   #[test]
-  fn no_deprecated_deno_api_valid() {
+  fn no_window_prefix_valid() {
     assert_lint_ok! {
       NoWindowPrefix,
       "fetch();",
@@ -377,7 +377,7 @@ mod tests {
   }
 
   #[test]
-  fn no_deprecated_deno_api_invalid() {
+  fn no_window_prefix_invalid() {
     assert_lint_err! {
       NoWindowPrefix,
       MESSAGE,

www/static/docs.json

@@ -561,6 +561,13 @@
       "recommended"
     ]
   },
+  {
+    "code": "no-window",
+    "docs": "Disallows the use of the `window` object.\n\nUsing the `window` global is deprecated and scheduled for removal in Deno 2.0.\nDeno does not have a window and `typeof window === \"undefined\"` is often used to\ntell if the code is running in the browser.\n\n### Invalid:\n\n```typescript\nconst a = await window.fetch(\"https://deno.land\");\n\nconst b = window.Deno.metrics();\nconsole.log(window);\n\nwindow.addEventListener(\"load\", () => {\n  console.log(\"Loaded.\");\n});\n```\n\n### Valid:\n\n```typescript\nconst a1 = await fetch(\"https://deno.land\");\nconst a2 = await globalThis.fetch(\"https://deno.land\");\nconst a3 = await self.fetch(\"https://deno.land\");\n\nconst b1 = Deno.metrics();\nconst b2 = globalThis.Deno.metrics();\nconst b3 = self.Deno.metrics();\nconsole.log(globalThis);\n\naddEventListener(\"load\", () => {\n  console.log(\"Loaded.\");\n});\n```\n",
+    "tags": [
+      "recommended"
+    ]
+  },
   {
     "code": "no-window-prefix",
     "docs": "Disallows the use of Web APIs via the `window` object.\n\nIn most situations, the global variable `window` works like `globalThis`. For\nexample, you could call the `fetch` API like `window.fetch(..)` instead of\n`fetch(..)` or `globalThis.fetch(..)`. In Web Workers, however, `window` is not\navailable, but instead `self`, `globalThis`, or no prefix work fine. Therefore,\nfor compatibility between Web Workers and other contexts, it's highly\nrecommended to not access global properties via `window`.\n\nSome APIs, including `window.alert`, `window.location` and `window.history`, are\nallowed to call with `window` because these APIs are not supported or have\ndifferent meanings in Workers. In other words, this lint rule complains about\nthe use of `window` only if it's completely replaceable with `self`,\n`globalThis`, or no prefix.\n\n### Invalid:\n\n```typescript\nconst a = await window.fetch(\"https://deno.land\");\n\nconst b = window.Deno.metrics();\n```\n\n### Valid:\n\n```typescript\nconst a1 = await fetch(\"https://deno.land\");\nconst a2 = await globalThis.fetch(\"https://deno.land\");\nconst a3 = await self.fetch(\"https://deno.land\");\n\nconst b1 = Deno.metrics();\nconst b2 = globalThis.Deno.metrics();\nconst b3 = self.Deno.metrics();\n\n// `alert` is allowed to call with `window` because it's not supported in Workers\nwindow.alert(\"🍣\");\n\n// `location` is also allowed\nwindow.location.host;\n```\n",