Improve JS interception when using ESM imports (e.g. node-fetch)

This is not a proper fix. We don't yet use loaded hooks, because they're
experimental, apparently _extremely_ likely to change in future, and
setting the option would cause issues with older node versions.

We can look at this in future once the API has stabilised (by doing
version detection in the PATH wrapper) but for now we can solve the
immediate issue by just enabling global-agent 100% of the time
regardless, which avoids issues with hooks not firing for ESM
node-fetch. I think ESM usage in Node is still not widespread, so this
should be enough to keep things usable in the short term.

Author: pimterry

overrides/js/prepend-node.js

@@ -7,33 +7,11 @@
  * plus tweaks various other HTTP clients that need nudges, so they
  * all correctly pick up the proxy from the environment.
  *
- * Tested against Node 6, 8, 10, 12 and 14.
-*/
+ * Tested against Node 6, 8, 10, 12, 14, 16 & 18.
+ */
 
 const wrapModule = require('./wrap-require');
 
-let httpAlreadyIntercepted = false;
-
-function interceptAllHttp() {
-    if (httpAlreadyIntercepted) return;
-    httpAlreadyIntercepted = true;
-
-    const MAJOR_NODEJS_VERSION = parseInt(process.version.slice(1).split('.')[0], 10);
-
-    if (MAJOR_NODEJS_VERSION >= 10) {
-        // `global-agent` works with Node.js v10 and above.
-        const globalAgent = require('global-agent');
-        globalAgent.bootstrap();
-    } else {
-        // `global-tunnel-ng` works only with Node.js v10 and below.
-        const globalTunnel = require('global-tunnel-ng');
-        globalTunnel.initialize();
-    }
-}
-
-wrapModule('http', interceptAllHttp, true);
-wrapModule('https', interceptAllHttp, true);
-
 wrapModule('axios', function wrapAxios (loadedModule) {
     // Global agent handles this automatically, if used (i.e. Node >= 10)
     if (global.GLOBAL_AGENT) return;
@@ -121,4 +99,17 @@ wrapModule('stripe', function wrapStripe (loadedModule) {
         loadedModule,
         { INTERCEPTED_BY_HTTPTOOLKIT: true }
     );
-});
+});
+
+// We always install a global HTTP agent, to ensure that everything using the base HTTP module is intercepted
+// by default. This avoids issues where hooks don't fire on ESM imports by just enabling this in all cases.
+const MAJOR_NODEJS_VERSION = parseInt(process.version.slice(1).split('.')[0], 10);
+if (MAJOR_NODEJS_VERSION >= 10) {
+    // `global-agent` works with Node.js v10 and above.
+    const globalAgent = require('global-agent');
+    globalAgent.bootstrap();
+} else {
+    // `global-tunnel-ng` works only with Node.js v10 and below.
+    const globalTunnel = require('global-tunnel-ng');
+    globalTunnel.initialize();
+}

overrides/js/wrap-require.js

@@ -4,6 +4,10 @@
  * This modules intercepts all require calls. For all modules previously
  * registered via wrapModule, it runs the registered wrapper on the loaded
  * module before it is returned to the original require() call.
+ *
+ * This only works for require(), not for ESM Import. Node.js import hooks
+ * are very experimental and not yet usable, but we should extend this to
+ * support those in future: https://github.com/nodejs/modules/issues/351
  */
 
 // Grab the built-in module loader that we're going to intercept

test/fixtures/terminal/js-test-script.js

@@ -1,4 +1,6 @@
 // Test built-ins against their specific protocol
+require('node:http').get('http://example.test/js/http');
+require('node:https').get('https://example.test/js/https');
 require('http').get('http://example.test/js/http');
 require('https').get('https://example.test/js/https');