typescript: Support definite assignment assertion (#7159)

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

@@ -99,10 +99,13 @@ export function ClassProperty(node: Object) {
     this.print(node.key, node);
   }
 
-  if (node.optional) {
   // TS
+  if (node.optional) {
     this.token("?");
   }
+  if (node.definite) {
+    this.token("!");
+  }
 
   this.print(node.typeAnnotation, node);
   if (node.value) {

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

@@ -290,6 +290,7 @@ export function VariableDeclaration(node: Object, parent: Object) {
 
 export function VariableDeclarator(node: Object) {
   this.print(node.id, node);
+  if (node.definite) this.token("!"); // TS
   this.print(node.id.typeAnnotation, node);
   if (node.init) {
     this.space();

packages/babel-generator/test/fixtures/typescript/class-properties/input.js

@@ -3,4 +3,6 @@ class C {
     x?;
     x: number;
     x: number = 1;
+    x!;
+    x!: number;
 }

packages/babel-generator/test/fixtures/typescript/class-properties/output.js

@@ -3,4 +3,6 @@ class C {
   x?;
   x: number;
   x: number = 1;
+  x!;
+  x!: number;
 }

packages/babel-generator/test/fixtures/typescript/variable-declarator-exclamation/actual.js

@@ -0,0 +1 @@
+let x!: number;

packages/babel-generator/test/fixtures/typescript/variable-declarator-exclamation/expected.js

@@ -0,0 +1 @@
+let x!: number;

packages/babel-plugin-transform-typescript/src/index.js

@@ -79,6 +79,10 @@ export default function() {
         if (path.node.declare) path.remove();
       },
 
+      VariableDeclarator({ node }) {
+        if (node.definite) node.definite = null;
+      },
+
       ClassMethod(path) {
         const { node } = path;
 
@@ -154,7 +158,9 @@ export default function() {
 
         if (node.accessibility) node.accessibility = null;
         if (node.abstract) node.abstract = null;
+        if (node.readonly) node.readonly = null;
         if (node.optional) node.optional = null;
+        if (node.definite) node.definite = null;
         if (node.typeAnnotation) node.typeAnnotation = null;
       },
 

packages/babel-plugin-transform-typescript/test/fixtures/class/properties/input.js

@@ -1,4 +1,5 @@
 class C {
     public a?: number;
     private b: number = 0;
+    readonly c!: number = 1;
 }

packages/babel-plugin-transform-typescript/test/fixtures/class/properties/output.js

@@ -1,3 +1,4 @@
 class C {
   b = 0;
+  c = 1;
 }

packages/babel-plugin-transform-typescript/test/fixtures/variable-declaration/exclamation/actual.js

@@ -0,0 +1 @@
+let x!: number;

packages/babel-plugin-transform-typescript/test/fixtures/variable-declaration/exclamation/expected.js

@@ -0,0 +1 @@
+let x;

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

@@ -836,6 +836,10 @@ defineType("VariableDeclarator", {
     id: {
       validate: assertNodeType("LVal"),
     },
+    definite: {
+      optional: true,
+      validate: assertValueType("boolean"),
+    },
     init: {
       optional: true,
       validate: assertNodeType("Expression"),

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

@@ -36,6 +36,10 @@ defineType("ClassProperty", {
       validate: assertNodeType("Expression"),
       optional: true,
     },
+    definite: {
+      validate: assertValueType("boolean"),
+      optional: true,
+    },
     typeAnnotation: {
       validate: assertNodeType("TypeAnnotation", "TSTypeAnnotation", "Noop"),
       optional: true,

packages/babylon/src/plugins/typescript.js

@@ -1691,6 +1691,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     parseClassProperty(node: N.ClassProperty): N.ClassProperty {
+      if (!node.optional && this.eat(tt.bang)) {
+        node.definite = true;
+      }
+
       const type = this.tsTryParseTypeAnnotation();
       if (type) node.typeAnnotation = type;
       return super.parseClassProperty(node);
@@ -1752,6 +1756,10 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     // `let x: number;`
     parseVarHead(decl: N.VariableDeclarator): void {
       super.parseVarHead(decl);
+      if (decl.id.type === "Identifier" && this.eat(tt.bang)) {
+        decl.definite = true;
+      }
+
       const type = this.tsTryParseTypeAnnotation();
       if (type) {
         decl.id.typeAnnotation = type;
@@ -1980,7 +1988,9 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     }
 
     isClassProperty(): boolean {
-      return this.match(tt.colon) || super.isClassProperty();
+      return (
+        this.match(tt.bang) || this.match(tt.colon) || super.isClassProperty()
+      );
     }
 
     parseMaybeDefault(...args): N.Pattern {

packages/babylon/src/types.js

@@ -326,6 +326,9 @@ export type VariableDeclarator = NodeBase & {
   type: "VariableDeclarator",
   id: Pattern,
   init: ?Expression,
+
+  // TypeScript only:
+  definite?: true,
 };
 
 // Misc
@@ -696,6 +699,7 @@ export type ClassProperty = ClassMemberBase & {
 
   // TypeScript only: (TODO: Not in spec)
   readonly?: true,
+  definite?: true,
 };
 
 export type ClassPrivateProperty = NodeBase & {

packages/babylon/test/fixtures/typescript/class/properties/input.js

@@ -3,4 +3,6 @@ class C {
     x?;
     x: number;
     x: number = 1;
+    x!;
+    x!: number;
 }

packages/babylon/test/fixtures/typescript/class/properties/output.json

@@ -1,28 +1,28 @@
 {
   "type": "File",
   "start": 0,
-  "end": 60,
+  "end": 84,
   "loc": {
     "start": {
       "line": 1,
       "column": 0
     },
     "end": {
-      "line": 6,
+      "line": 8,
       "column": 1
     }
   },
   "program": {
     "type": "Program",
     "start": 0,
-    "end": 60,
+    "end": 84,
     "loc": {
       "start": {
         "line": 1,
         "column": 0
       },
       "end": {
-        "line": 6,
+        "line": 8,
         "column": 1
       }
     },
@@ -31,14 +31,14 @@
       {
         "type": "ClassDeclaration",
         "start": 0,
-        "end": 60,
+        "end": 84,
         "loc": {
           "start": {
             "line": 1,
             "column": 0
           },
           "end": {
-            "line": 6,
+            "line": 8,
             "column": 1
           }
         },
@@ -63,14 +63,14 @@
         "body": {
           "type": "ClassBody",
           "start": 8,
-          "end": 60,
+          "end": 84,
           "loc": {
             "start": {
               "line": 1,
               "column": 8
             },
             "end": {
-              "line": 6,
+              "line": 8,
               "column": 1
             }
           },
@@ -294,6 +294,108 @@
                 },
                 "value": 1
               }
+            },
+            {
+              "type": "ClassProperty",
+              "start": 63,
+              "end": 66,
+              "loc": {
+                "start": {
+                  "line": 6,
+                  "column": 4
+                },
+                "end": {
+                  "line": 6,
+                  "column": 7
+                }
+              },
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start": 63,
+                "end": 64,
+                "loc": {
+                  "start": {
+                    "line": 6,
+                    "column": 4
+                  },
+                  "end": {
+                    "line": 6,
+                    "column": 5
+                  },
+                  "identifierName": "x"
+                },
+                "name": "x"
+              },
+              "computed": false,
+              "definite": true,
+              "value": null
+            },
+            {
+              "type": "ClassProperty",
+              "start": 71,
+              "end": 82,
+              "loc": {
+                "start": {
+                  "line": 7,
+                  "column": 4
+                },
+                "end": {
+                  "line": 7,
+                  "column": 15
+                }
+              },
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start": 71,
+                "end": 72,
+                "loc": {
+                  "start": {
+                    "line": 7,
+                    "column": 4
+                  },
+                  "end": {
+                    "line": 7,
+                    "column": 5
+                  },
+                  "identifierName": "x"
+                },
+                "name": "x"
+              },
+              "computed": false,
+              "definite": true,
+              "typeAnnotation": {
+                "type": "TSTypeAnnotation",
+                "start": 73,
+                "end": 81,
+                "loc": {
+                  "start": {
+                    "line": 7,
+                    "column": 6
+                  },
+                  "end": {
+                    "line": 7,
+                    "column": 14
+                  }
+                },
+                "typeAnnotation": {
+                  "type": "TSNumberKeyword",
+                  "start": 75,
+                  "end": 81,
+                  "loc": {
+                    "start": {
+                      "line": 7,
+                      "column": 8
+                    },
+                    "end": {
+                      "line": 7,
+                      "column": 14
+                    }
+                  }
+                }
+              },
+              "value": null
             }
           ]
         }

packages/babylon/test/fixtures/typescript/class/property-optional-definite-assignment-not-allowed/input.js

@@ -0,0 +1,3 @@
+class C {
+  x?!: number;
+}

packages/babylon/test/fixtures/typescript/class/property-optional-definite-assignment-not-allowed/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected \";\" (2:4)"
+}

packages/babylon/test/fixtures/typescript/variable-declarator/definite-assignment-not-allowed/input.js

@@ -0,0 +1 @@
+let {}! = {};

packages/babylon/test/fixtures/typescript/variable-declarator/definite-assignment-not-allowed/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Complex binding patterns require an initialization value (1:6)"
+}

packages/babylon/test/fixtures/typescript/variable-declarator/definite-assignment/input.js

@@ -0,0 +1 @@
+let x!: number;

packages/babylon/test/fixtures/typescript/variable-declarator/definite-assignment/output.json

@@ -0,0 +1,116 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 15,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 15
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 15,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 15
+      }
+    },
+    "sourceType": "module",
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start": 0,
+        "end": 15,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 15
+          }
+        },
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start": 4,
+            "end": 14,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 4
+              },
+              "end": {
+                "line": 1,
+                "column": 14
+              }
+            },
+            "id": {
+              "type": "Identifier",
+              "start": 4,
+              "end": 14,
+              "loc": {
+                "start": {
+                  "line": 1,
+                  "column": 4
+                },
+                "end": {
+                  "line": 1,
+                  "column": 14
+                },
+                "identifierName": "x"
+              },
+              "name": "x",
+              "typeAnnotation": {
+                "type": "TSTypeAnnotation",
+                "start": 6,
+                "end": 14,
+                "loc": {
+                  "start": {
+                    "line": 1,
+                    "column": 6
+                  },
+                  "end": {
+                    "line": 1,
+                    "column": 14
+                  }
+                },
+                "typeAnnotation": {
+                  "type": "TSNumberKeyword",
+                  "start": 8,
+                  "end": 14,
+                  "loc": {
+                    "start": {
+                      "line": 1,
+                      "column": 8
+                    },
+                    "end": {
+                      "line": 1,
+                      "column": 14
+                    }
+                  }
+                }
+              }
+            },
+            "definite": true,
+            "init": null
+          }
+        ],
+        "kind": "let"
+      }
+    ],
+    "directives": []
+  }
+}