Typescript - Tuples can include rest elements (#8805)

packages/babel-generator/src/generators/typescript.js

@@ -246,6 +246,11 @@ export function TSOptionalType(node) {
   this.token("?");
 }
 
+export function TSRestType(node) {
+  this.token("...");
+  this.print(node.typeAnnotation, node);
+}
+
 export function TSUnionType(node) {
   this.tsPrintUnionOrIntersectionType(node, "|");
 }

packages/babel-generator/test/fixtures/typescript/tuple-rest/input.js

@@ -0,0 +1 @@
+let x: [string, ...number[]]

packages/babel-generator/test/fixtures/typescript/tuple-rest/output.js

@@ -0,0 +1 @@
+let x: [string, ...number[]];

packages/babel-parser/src/plugins/typescript.js

@@ -511,7 +511,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     tsParseTupleElementType(): N.TsType {
+      // parses `...TsType[]`
+      if (this.match(tt.ellipsis)) {
+        const restNode: N.TsRestType = this.startNode();
+        this.next(); // skips ellipsis
+        restNode.typeAnnotation = this.tsParseType();
+        return this.finishNode(restNode, "TSRestType");
+      }
+
       const type = this.tsParseType();
+      // parses `TsType?`
       if (this.eat(tt.question)) {
         const optionalTypeNode: N.TsOptionalType = this.startNodeAtNode(type);
         optionalTypeNode.typeAnnotation = type;

packages/babel-parser/src/types.js

@@ -1105,6 +1105,7 @@ export type TsType =
   | TsArrayType
   | TsTupleType
   | TsOptionalType
+  | TsRestType
   | TsUnionOrIntersectionType
   | TsConditionalType
   | TsInferType
@@ -1190,6 +1191,11 @@ export type TsOptionalType = TsTypeBase & {
   typeAnnotation: TsType,
 };
 
+export type TsRestType = TsTypeBase & {
+  type: "TSRestType",
+  typeAnnotation: TsType,
+};
+
 export type TsUnionOrIntersectionType = TsUnionType | TsIntersectionType;
 
 export type TsUnionOrIntersectionTypeBase = TsTypeBase & {

packages/babel-parser/test/fixtures/typescript/types/tuple-rest/input.js

@@ -0,0 +1 @@
+let x: [string, ...number[]]

packages/babel-parser/test/fixtures/typescript/types/tuple-rest/output.json

@@ -0,0 +1,178 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 28,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 28
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 28,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 28
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 28,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 28
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 28,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 1,
+                "column": 28
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 28,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 28
+                },
+                "identifierName": "x"
+              },
+              "name": "x",
+              "typeAnnotation": {
+                "type": "TSTypeAnnotation",
+                "start": 5,
+                "end": 28,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 5
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 28
+                  }
+                },
+                "typeAnnotation": {
+                  "type": "TSTupleType",
+                  "start": 7,
+                  "end": 28,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 7
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 28
+                    }
+                  },
+                  "elementTypes": [
+                    {
+                      "type": "TSStringKeyword",
+                      "start": 8,
+                      "end": 14,
+                      "loc": {
+                        "start": {
+                          "line": 1,
+                          "column": 8
+                        },
+                        "end": {
+                          "line": 1,
+                          "column": 14
+                        }
+                      }
+                    },
+                    {
+                      "type": "TSRestType",
+                      "start": 16,
+                      "end": 27,
+                      "loc": {
+                        "start": {
+                          "line": 1,
+                          "column": 16
+                        },
+                        "end": {
+                          "line": 1,
+                          "column": 27
+                        }
+                      },
+                      "typeAnnotation": {
+                        "type": "TSArrayType",
+                        "start": 19,
+                        "end": 27,
+                        "loc": {
+                          "start": {
+                            "line": 1,
+                            "column": 19
+                          },
+                          "end": {
+                            "line": 1,
+                            "column": 27
+                          }
+                        },
+                        "elementType": {
+                          "type": "TSNumberKeyword",
+                          "start": 19,
+                          "end": 25,
+                          "loc": {
+                            "start": {
+                              "line": 1,
+                              "column": 19
+                            },
+                            "end": {
+                              "line": 1,
+                              "column": 25
+                            }
+                          }
+                        }
+                      }
+                    }
+                  ]
+                }
+              }
+            },
+            "init": null
+          }
+        ],
+        "kind": "let"
+      }
+    ],
+    "directives": []
+  }
+}

packages/babel-plugin-transform-typescript/test/fixtures/function/tuple-parameter/input.js

@@ -1 +1 @@
-function foo(...args: [number, string?]) {}
+function foo(...args: [number, string?, ...number[]]) {}

packages/babel-types/src/definitions/typescript.js

@@ -221,6 +221,14 @@ defineType("TSOptionalType", {
   },
 });
 
+defineType("TSRestType", {
+  aliases: ["TSType"],
+  visitor: ["typeAnnotation"],
+  fields: {
+    typeAnnotation: validateType("TSType"),
+  },
+});
+
 const unionOrIntersection = {
   aliases: ["TSType"],
   visitor: ["types"],