Merge pull request #3365 from jridgewell/replace-implicit-arrow-with-block

Replace arrow expression body with block statement

packages/babel-core/test/path.js

@@ -19,4 +19,138 @@ suite("traversal path", function () {
 
     chai.expect(actualCode).to.be.equal("console.whatever();");
   });
+
+  test("replaceWith (arrow expression body to block statement body)", function () {
+    var expectCode = "var fn = () => true;";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ArrowFunctionExpression: function (path) {
+            path.get("body").replaceWith({
+              type: "BlockStatement",
+              body: [{
+                type: "ReturnStatement",
+                argument: {
+                  type: "BooleanLiteral",
+                  value: true
+                }
+              }]
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("var fn = () => {\n  return true;\n};");
+  });
+
+  test("replaceWith (arrow block statement body to expression body)", function () {
+    var expectCode = "var fn = () => { return true; }";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ArrowFunctionExpression: function (path) {
+            path.get("body").replaceWith({
+              type: "BooleanLiteral",
+              value: true
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("var fn = () => true;");
+  });
+
+  test("replaceWith (for-in left expression to variable declaration)", function () {
+    var expectCode = "for (KEY in right);";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ForInStatement: function (path) {
+            path.get("left").replaceWith({
+              type: "VariableDeclaration",
+              kind: "var",
+              declarations: [{
+                type: "VariableDeclarator",
+                id: {
+                  type: "Identifier",
+                  name: "KEY"
+                }
+              }]
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("for (var KEY in right);");
+  });
+
+  test("replaceWith (for-in left variable declaration to expression)", function () {
+    var expectCode = "for (var KEY in right);";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ForInStatement: function (path) {
+            path.get("left").replaceWith({
+              type: "Identifier",
+              name: "KEY"
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("for (KEY in right);");
+  });
+
+  test("replaceWith (for-loop left expression to variable declaration)", function () {
+    var expectCode = "for (KEY;;);";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ForStatement: function (path) {
+            path.get("init").replaceWith({
+              type: "VariableDeclaration",
+              kind: "var",
+              declarations: [{
+                type: "VariableDeclarator",
+                id: {
+                  type: "Identifier",
+                  name: "KEY"
+                }
+              }]
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("for (var KEY;;);");
+  });
+
+  test("replaceWith (for-loop left variable declaration to expression)", function () {
+    var expectCode = "for (var KEY;;);";
+
+    var actualCode = transform(expectCode, {
+      plugins: [new Plugin({
+        visitor: {
+          ForStatement: function (path) {
+            path.get("init").replaceWith({
+              type: "Identifier",
+              name: "KEY"
+            });
+          }
+        }
+      })]
+    }).code;
+
+    chai.expect(actualCode).to.be.equal("for (KEY;;);");
+  });
 });