feat(compat): inject Node globals (#12342)

This commit adds automatic injection of Node globals when "--compat" flag
is present.

This is done by executing "https://deno.land/std/node/global.ts" as a "side module",
before main module is executed.

This commit makes "--compat" required to be used with "--unstable" flag, as some
of Node globals require unstable Deno APIs.

1 files changed, 12 insertions, 1 deletions

diff --git a/cli/compat.rs b/cli/compat.rs
index eb67f4d12..4b64a501d 100644
--- a/cli/compat.rs
+++ b/cli/compat.rs
@@ -1,7 +1,10 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
+use deno_core::url::Url;
 use std::collections::HashMap;
 
+static STD_NODE: &str = "https://deno.land/std/node/";
+
 static SUPPORTED_MODULES: &[&str] = &[
   "assert",
   "assert/strict",
@@ -47,12 +50,20 @@ static SUPPORTED_MODULES: &[&str] = &[
   "zlib",
 ];
 
+pub fn get_node_globals_url() -> Url {
+  Url::parse(&format!("{}global.ts", STD_NODE)).unwrap()
+}
+
+/// Create a map that can be used to update import map.
+///
+/// Keys are built-in Node modules (and built-ins prefixed with "node:"), while
+/// values are URLs pointing to relevant files in deno.land/std/node/ directory.
 pub fn get_mapped_node_builtins() -> HashMap<String, String> {
   let mut mappings = HashMap::new();
 
   for module in SUPPORTED_MODULES {
     // TODO(bartlomieju): this is unversioned, and should be fixed to use latest stable?
-    let module_url = format!("https://deno.land/std/node/{}.ts", module);
+    let module_url = format!("{}{}.ts", STD_NODE, module);
     mappings.insert(module.to_string(), module_url.clone());
 
     // Support for `node:<module_name>`