From da79c90f2af2627e8ee383569416749fa8338fde Mon Sep 17 00:00:00 2001
From: JuniorTour <juniortour@qq.com>
Date: Thu, 16 Sep 2021 16:24:11 -0500
Subject: [PATCH] fix(babel-parser): Allow line break before `assert` return
 type (#13771)

---
 .../src/plugins/typescript/index.js           |   6 +-
 .../input.ts                                  |   2 +
 .../output.json                               | 184 ++++++++++++++++++
 3 files changed, 187 insertions(+), 5 deletions(-)
 create mode 100644 packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/input.ts
 create mode 100644 packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/output.json

diff --git a/packages/babel-parser/src/plugins/typescript/index.js b/packages/babel-parser/src/plugins/typescript/index.js
index 71ed89592c..b2f42b5835 100644
--- a/packages/babel-parser/src/plugins/typescript/index.js
+++ b/packages/babel-parser/src/plugins/typescript/index.js
@@ -1316,11 +1316,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     tsParseTypePredicateAsserts(): boolean {
-      if (
-        !this.match(tt.name) ||
-        this.state.value !== "asserts" ||
-        this.hasPrecedingLineBreak()
-      ) {
+      if (!this.match(tt.name) || this.state.value !== "asserts") {
         return false;
       }
       const containsEsc = this.state.containsEsc;
diff --git a/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/input.ts b/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/input.ts
new file mode 100644
index 0000000000..404da1ba13
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/input.ts
@@ -0,0 +1,2 @@
+function assert(condition: any):
+asserts condition {}
diff --git a/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/output.json b/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/output.json
new file mode 100644
index 0000000000..c86ab9a36f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/typescript/assert-predicate/function-declaration-with-line-break/output.json
@@ -0,0 +1,184 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 53,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 20
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 53,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 20
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start": 0,
+        "end": 53,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 20
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 9,
+          "end": 15,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 9
+            },
+            "end": {
+              "line": 1,
+              "column": 15
+            },
+            "identifierName": "assert"
+          },
+          "name": "assert"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start": 16,
+            "end": 30,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 16
+              },
+              "end": {
+                "line": 1,
+                "column": 30
+              },
+              "identifierName": "condition"
+            },
+            "name": "condition",
+            "typeAnnotation": {
+              "type": "TSTypeAnnotation",
+              "start": 25,
+              "end": 30,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 25
+                },
+                "end": {
+                  "line": 1,
+                  "column": 30
+                }
+              },
+              "typeAnnotation": {
+                "type": "TSAnyKeyword",
+                "start": 27,
+                "end": 30,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 27
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 30
+                  }
+                }
+              }
+            }
+          }
+        ],
+        "returnType": {
+          "type": "TSTypeAnnotation",
+          "start": 31,
+          "end": 50,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 31
+            },
+            "end": {
+              "line": 2,
+              "column": 17
+            }
+          },
+          "typeAnnotation": {
+            "type": "TSTypePredicate",
+            "start": 33,
+            "end": 50,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 0
+              },
+              "end": {
+                "line": 2,
+                "column": 17
+              }
+            },
+            "parameterName": {
+              "type": "Identifier",
+              "start": 41,
+              "end": 50,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 8
+                },
+                "end": {
+                  "line": 2,
+                  "column": 17
+                },
+                "identifierName": "condition"
+              },
+              "name": "condition"
+            },
+            "asserts": true,
+            "typeAnnotation": null
+          }
+        },
+        "body": {
+          "type": "BlockStatement",
+          "start": 51,
+          "end": 53,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 18
+            },
+            "end": {
+              "line": 2,
+              "column": 20
+            }
+          },
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}