Allow Flowtype's imports and exports when sourceType:script is set. (#…

…771)

src/parser/statement.js

@@ -129,37 +129,34 @@ export default class StatementParser extends ExpressionParser {
       case tt.semi:
         return this.parseEmptyStatement(node);
       case tt._export:
-      case tt._import:
+      case tt._import: {
         if (
           (this.hasPlugin("dynamicImport") &&
             this.lookahead().type === tt.parenL) ||
           (this.hasPlugin("importMeta") && this.lookahead().type === tt.dot)
         )
           break;
 
-        if (!this.options.allowImportExportEverywhere) {
-          if (!topLevel) {
-            this.raise(
-              this.state.start,
-              "'import' and 'export' may only appear at the top level",
-            );
-          }
-
-          if (!this.inModule) {
-            this.raise(
-              this.state.start,
-              `'import' and 'export' may appear only with 'sourceType: "module"'`,
-            );
-          }
+        if (!this.options.allowImportExportEverywhere && !topLevel) {
+          this.raise(
+            this.state.start,
+            "'import' and 'export' may only appear at the top level",
+          );
         }
 
         this.next();
+
+        let result;
         if (starttype == tt._import) {
-          return this.parseImport(node);
+          result = this.parseImport(node);
         } else {
-          return this.parseExport(node);
+          result = this.parseExport(node);
         }
 
+        this.assertModuleNodeAllowed(node);
+
+        return result;
+      }
       case tt.name:
         if (this.state.value === "async") {
           // peek ahead and see if next token is a function
@@ -193,6 +190,15 @@ export default class StatementParser extends ExpressionParser {
     }
   }
 
+  assertModuleNodeAllowed(node: N.Node): void {
+    if (!this.options.allowImportExportEverywhere && !this.inModule) {
+      this.raise(
+        node.start,
+        `'import' and 'export' may appear only with 'sourceType: "module"'`,
+      );
+    }
+  }
+
   takeDecorators(node: N.HasDecorators): void {
     const decorators = this.state.decoratorStack[
       this.state.decoratorStack.length - 1

src/plugins/flow.js

@@ -1498,6 +1498,22 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return node;
     }
 
+    assertModuleNodeAllowed(node: N.Node) {
+      if (
+        (node.type === "ImportDeclaration" &&
+          (node.importKind === "type" || node.importKind === "typeof")) ||
+        (node.type === "ExportNamedDeclaration" &&
+          node.exportKind === "type") ||
+        (node.type === "ExportAllDeclaration" && node.exportKind === "type")
+      ) {
+        // Allow Flowtype imports and exports in all conditions because
+        // Flow itself does not care about 'sourceType'.
+        return;
+      }
+
+      super.assertModuleNodeAllowed(node);
+    }
+
     parseExport(node: N.ExportNamedDeclaration): N.ExportNamedDeclaration {
       node = super.parseExport(node);
       if (

test/fixtures/flow/sourcetype-script/export-named/actual.js

@@ -0,0 +1,2 @@
+export type Foo = number;
+export opaque type Foo = number;

test/fixtures/flow/sourcetype-script/export-named/expected.json

@@ -0,0 +1,167 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 58,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 32
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 58,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 32
+      }
+    },
+    "sourceType": "script",
+    "body": [
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 0,
+        "end": 25,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 25
+          }
+        },
+        "specifiers": [],
+        "source": null,
+        "exportKind": "type",
+        "declaration": {
+          "type": "TypeAlias",
+          "start": 7,
+          "end": 25,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 7
+            },
+            "end": {
+              "line": 1,
+              "column": 25
+            }
+          },
+          "id": {
+            "type": "Identifier",
+            "start": 12,
+            "end": 15,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 12
+              },
+              "end": {
+                "line": 1,
+                "column": 15
+              },
+              "identifierName": "Foo"
+            },
+            "name": "Foo"
+          },
+          "typeParameters": null,
+          "right": {
+            "type": "NumberTypeAnnotation",
+            "start": 18,
+            "end": 24,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 18
+              },
+              "end": {
+                "line": 1,
+                "column": 24
+              }
+            }
+          }
+        }
+      },
+      {
+        "type": "ExportNamedDeclaration",
+        "start": 26,
+        "end": 58,
+        "loc": {
+          "start": {
+            "line": 2,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 32
+          }
+        },
+        "specifiers": [],
+        "source": null,
+        "exportKind": "type",
+        "declaration": {
+          "type": "OpaqueType",
+          "start": 33,
+          "end": 58,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 7
+            },
+            "end": {
+              "line": 2,
+              "column": 32
+            }
+          },
+          "id": {
+            "type": "Identifier",
+            "start": 45,
+            "end": 48,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 19
+              },
+              "end": {
+                "line": 2,
+                "column": 22
+              },
+              "identifierName": "Foo"
+            },
+            "name": "Foo"
+          },
+          "typeParameters": null,
+          "supertype": null,
+          "impltype": {
+            "type": "NumberTypeAnnotation",
+            "start": 51,
+            "end": 57,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 25
+              },
+              "end": {
+                "line": 2,
+                "column": 31
+              }
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

test/fixtures/flow/sourcetype-script/export-star/actual.js

@@ -0,0 +1 @@
+export type * from "foo";

test/fixtures/flow/sourcetype-script/export-star/expected.json

@@ -0,0 +1,70 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 25,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 25
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 25,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 25
+      }
+    },
+    "sourceType": "script",
+    "body": [
+      {
+        "type": "ExportAllDeclaration",
+        "start": 0,
+        "end": 25,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 25
+          }
+        },
+        "exportKind": "type",
+        "source": {
+          "type": "StringLiteral",
+          "start": 19,
+          "end": 24,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 19
+            },
+            "end": {
+              "line": 1,
+              "column": 24
+            }
+          },
+          "extra": {
+            "rawValue": "foo",
+            "raw": "\"foo\""
+          },
+          "value": "foo"
+        }
+      }
+    ],
+    "directives": []
+  }
+}

test/fixtures/flow/sourcetype-script/import/actual.js

@@ -0,0 +1,2 @@
+import type { Foo } from "";
+import typeof Foo2 from "";