union types and dicriminators

Signed-off-by: ivan katliarchuk <[email protected]>

Author: ivankatliarchuk

2-understand/s6-advanced-types/Makefile

@@ -0,0 +1,12 @@
+help:
+	@printf "Usage: make [target] [VARIABLE=value]\nTargets:\n"
+	@grep -E '^[a-zA-Z0-9_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
+
+run-intersections: ## Run intersections
+	@deno run intersection.ts
+
+run-type-guards: ## Run type guards
+	@deno run type-guards.ts
+
+run-disc-unions: ## Run discriminated unions
+	@deno run disc-union.ts

2-understand/s6-advanced-types/disc-union.ts

@@ -0,0 +1,28 @@
+// discriminated unions
+// https://www.udemy.com/course/understanding-typescript/learn/lecture/16893894#overview
+
+interface Bird {
+  type: 'bird';
+  flyingSpeed: number;
+}
+
+interface Horse {
+  type: 'horse';
+  runningSpeed: number;
+}
+
+type Animal = Bird | Hose;
+
+function moveAnimal(animal: Animal) {
+  let speed;
+  switch (animal.type) {
+    case 'bird':
+      speed = animal.flyingSpeed;
+      break;
+    case 'horse':
+      speed = animal.runningSpeed;
+  }
+  console.log('Moving with speed: ' + speed);
+}
+
+moveAnimal({ type: 'bird', runningSpeed: 70})

2-understand/s6-advanced-types/intersection.ts

@@ -0,0 +1,25 @@
+type Admin = {
+  name: string;
+  privileges: string[];
+};
+
+interface Employee {
+  name: string;
+  startDate: Date;
+};
+
+type ElevatedEmployee = Admin & Employee;
+// or
+interface IElevatedEmployee extends Employee, Admin { }
+
+const e1: ElevatedEmployee = {
+  name: 'Max',
+  privileges: ['create-server'],
+  startDate: new Date()
+}
+
+console.log(e1);
+
+type Combinable = string | number;
+type Numeric = number | boolean;
+type Universal = Combinable & Numeric;

2-understand/s6-advanced-types/tsconfig.json

@@ -3,6 +3,12 @@
     /* Basic Options */
     "target": "ES6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
     "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "lib": [
+      "dom",
+      "es6",
+      "dom.iterable",
+      "scripthost"
+    ],
     // "allowJs": true,                       /* Allow javascript files to be compiled. */
     // "checkJs": true,                       /* Report errors in .js files. */
     // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
@@ -43,7 +49,7 @@
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
     // "types": [],                           /* Type declaration files to be included in compilation. */
     // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
-    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    "esModuleInterop": true,                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
     // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */
 
     /* Source Map Options */
@@ -55,6 +61,9 @@
     /* Experimental Options */
     // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
     // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
+    "noUnusedLocals": true, /* Report errors on unused locals. */
+    "noUnusedParameters": true, /* Report errors on unused parameters. */
+    "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
   },
   "exclude": [
     "analytics.ts",

2-understand/s6-advanced-types/type-guards.ts

@@ -0,0 +1,62 @@
+
+type Combinable1 = string | number;
+type Numeric1 = number | boolean;
+type Universal1 = Combinable1 & Numeric1;
+
+function add(a: Combinable1, b: Combinable1) {
+  if (typeof a === 'string' || typeof b === 'string') {
+    return a.toString() + b.toString();
+  }
+  return a + b;
+}
+
+type UnknownEmployee = Employee | Admin;
+function printEmployeeInformation(emp: UnknownEmployee) {
+  console.log('Name: ' + emp.name);
+  if ('privileges' in emp) {
+    console.log('Privileges: ' + emp.privileges);
+  }
+  if ('startDate' in emp) {
+    console.log('Start Date: ' + emp.startDate);
+  }
+}
+
+const e1: ElevatedEmployee = {
+  name: 'Max',
+  privileges: ['create-server'],
+  startDate: new Date()
+}
+
+printEmployeeInformation(e1);
+printEmployeeInformation({name: 'Manu', startDate: new Date()});
+
+class Car {
+  drive() {
+    console.log('Driving....');
+  }
+}
+
+
+class Truck {
+  drive() {
+    console.log('Driving a track....');
+  }
+
+  loadCargo(amount: number) {
+    console.log('Loading cargo ...' + amount);
+  }
+}
+
+type Vehicle = Car | Truck;
+const v1 = new Car();
+const v2 = new Truck();
+
+function useVehicle(vehicle: Vehicle) {
+  vehicle.drive();
+  if (vehicle instanceof Truck) {
+    vehicle.loadCargo(1000);
+  }
+}
+
+useVehicle(v1);
+useVehicle(v2);