Port babel-parser changes from 2021-08-20 to 2021-12-30

src/parser/plugins/typescript.ts

@@ -672,7 +672,7 @@ function tsTryParseType(): void {
  */
 function tsParseTypePredicateOrAssertsPrefix(): boolean {
   const snapshot = state.snapshot();
-  if (isContextual(ContextualKeyword._asserts) && !hasPrecedingLineBreak()) {
+  if (isContextual(ContextualKeyword._asserts)) {
     // Normally this is `asserts x is T`, but at this point, it might be `asserts is T` (a user-
     // defined type guard on the `asserts` variable) or just a type called `asserts`.
     next();
@@ -1453,7 +1453,9 @@ export function tsStartParseFunctionParams(): void {
 // `let x: number;`
 export function tsAfterParseVarHead(): void {
   const oldIsType = pushTypeContext(0);
-  eat(tt.bang);
+  if (!hasPrecedingLineBreak()) {
+    eat(tt.bang);
+  }
   tsTryParseTypeAnnotation();
   popTypeContext(oldIsType);
 }

test/sucrase-test.ts

@@ -1513,4 +1513,36 @@ describe("sucrase", () => {
     `,
     );
   });
+
+  it("allows static blocks with a line break after the static keyword", () => {
+    assertResult(
+      `
+      class A {
+        static
+        {
+          console.log("hi");
+        }
+      }
+    `,
+      `"use strict";
+      class A {
+        static
+        {
+          console.log("hi");
+        }
+      }
+    `,
+    );
+  });
+
+  it("allows arrow functions with parameter object assignment", () => {
+    assertResult(
+      `
+      ({x = 1}) => null
+    `,
+      `"use strict";
+      ({x = 1}) => null
+    `,
+    );
+  });
 });

test/typescript-test.ts

@@ -3003,4 +3003,32 @@ describe("typescript transform", () => {
       {transforms: ["typescript"]},
     );
   });
+
+  it("allows a line break before an `asserts` clause", () => {
+    assertResult(
+      `
+      function assert(condition: any): 
+      asserts condition {}
+    `,
+      `
+      function assert(condition)
+ {}
+    `,
+      {transforms: ["typescript"]},
+    );
+  });
+
+  it("properly handles ASI for variable followed by exclamation point", () => {
+    assertResult(
+      `
+      let a
+      !function(){}()
+    `,
+      `
+      let a
+      !function(){}()
+    `,
+      {transforms: ["typescript"]},
+    );
+  });
 });