polymorphic this

Author: basarat

polymorphicThis/polymorphicThis.js

@@ -0,0 +1,25 @@
+var __extends = (this && this.__extends) || function (d, b) {
+    for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
+    function __() { this.constructor = d; }
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+};
+var A = (function () {
+    function A() {
+    }
+    A.prototype.foo = function () {
+        return this;
+    };
+    return A;
+})();
+var B = (function (_super) {
+    __extends(B, _super);
+    function B() {
+        _super.apply(this, arguments);
+    }
+    B.prototype.bar = function () {
+        return this;
+    };
+    return B;
+})(A);
+var b;
+var x = b.foo().bar();

polymorphicThis/polymorphicThis.ts

@@ -0,0 +1,14 @@
+class A {
+    foo() {
+        return this;
+    }
+}
+
+class B extends A {
+    bar() {
+        return this;
+    }
+}
+
+var b: B;
+var x = b.foo().bar();  // Fluent pattern works, type of x is B

polymorphicThis/tsconfig.json

@@ -0,0 +1,25 @@
+{
+    "compilerOptions": {
+        "target": "es5",
+        "module": "commonjs",
+        "moduleResolution": "node",
+        "isolatedModules": false,
+        "jsx": "react",
+        "experimentalDecorators": true,
+        "emitDecoratorMetadata": true,
+        "declaration": false,
+        "noImplicitAny": false,
+        "removeComments": true,
+        "noLib": false,
+        "preserveConstEnums": true,
+        "suppressImplicitAnyIndexErrors": true
+    },
+    "filesGlob": [
+        "./**/*.ts",
+        "./**/*.tsx",
+        "!./node_modules/**/*"
+    ],
+    "files": [
+        "./polymorphicThis.ts"
+    ]
+}