Avoid state cloning

babel · Feb 9, 2021 · 953bda2 · 953bda2
1 parent c5bcc1f
commit 953bda2
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Showing 2 changed files with 20 additions and 12 deletions.
diff --git a/packages/babel-parser/src/parser/util.js b/packages/babel-parser/src/parser/util.js
@@ -96,6 +96,12 @@ export default class UtilParser extends Tokenizer {
     );
   }
 
+  hasFollowingLineBreak(): boolean {
+    return lineBreak.test(
+      this.input.slice(this.state.end, this.nextTokenStart()),
+    );
+  }
+
   // TODO
 
   isLineTerminator(): boolean {

diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
@@ -1530,9 +1530,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             if (value === "global") {
               return this.tsParseAmbientExternalModuleDeclaration(nany);
             } else {
-              return this.tsTryParse(() =>
-                this.tsParseDeclaration(nany, value, /* next */ true),
-              );
+              return this.tsParseDeclaration(nany, value, /* next */ true);
             }
           }
         }
@@ -1619,20 +1617,24 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           break;
 
         case "module":
-          if (next) this.next();
-          if (!this.isLineTerminator()) {
-            if (this.match(tt.string)) {
-              return this.tsParseAmbientExternalModuleDeclaration(node);
-            } else if (this.match(tt.name)) {
-              return this.tsParseModuleOrNamespaceDeclaration(node);
+          if (!next || !this.hasFollowingLineBreak()) {
+            if (next) this.next();
+            if (!this.isLineTerminator()) {
+              if (this.match(tt.string)) {
+                return this.tsParseAmbientExternalModuleDeclaration(node);
+              } else if (this.match(tt.name)) {
+                return this.tsParseModuleOrNamespaceDeclaration(node);
+              }
             }
           }
           break;
 
         case "namespace":
-          if (next) this.next();
-          if (!this.isLineTerminator() && this.match(tt.name)) {
-            return this.tsParseModuleOrNamespaceDeclaration(node);
+          if (!next || !this.hasFollowingLineBreak()) {
+            if (next) this.next();
+            if (!this.isLineTerminator() && this.match(tt.name)) {
+              return this.tsParseModuleOrNamespaceDeclaration(node);
+            }
           }
           break;