Ex(Vinhnx): Typescript lesson

vinhnx/ex1.ts

@@ -0,0 +1,25 @@
+export interface IUser {
+	name: string;
+	age: number;
+	occupation: string
+};
+
+export const users: Array<IUser> = [
+	{
+			name: 'Max Mustermann',
+			age: 25,
+			occupation: 'Chimney sweep'
+	},
+	{
+			name: 'Kate Müller',
+			age: 23,
+			occupation: 'Astronaut'
+	}
+];
+
+export function logPerson(user: IUser) {
+	console.log(` - ${user.name}, ${user.age}`);
+}
+
+console.log('Users:');
+users.forEach(logPerson);

vinhnx/ex2.ts

@@ -0,0 +1,42 @@
+interface IUser {
+	name: string;
+	age: number;
+	occupation: string;
+}
+
+interface IAdmin {
+	name: string;
+	age: number;
+	role: string;
+}
+
+export type TPerson = IUser | IAdmin;
+
+export const persons: TPerson[] = [
+	{
+			name: 'Max Mustermann',
+			age: 25,
+			occupation: 'Chimney sweep'
+	},
+	{
+			name: 'Jane Doe',
+			age: 32,
+			role: 'Administrator'
+	},
+	{
+			name: 'Kate Müller',
+			age: 23,
+			occupation: 'Astronaut'
+	},
+	{
+			name: 'Bruce Willis',
+			age: 64,
+			role: 'World saver'
+	}
+];
+
+export function logPerson(user: TPerson) {
+	console.log(` - ${user.name}, ${user.age}`);
+}
+
+persons.forEach(logPerson);

vinhnx/ex3.ts

@@ -0,0 +1,50 @@
+interface User {
+	name: string;
+	age: number;
+	occupation: string;
+}
+
+interface Admin {
+	name: string;
+	age: number;
+	role: string;
+}
+
+export type Person = User | Admin;
+
+export const persons: Person[] = [
+	{
+			name: 'Max Mustermann',
+			age: 25,
+			occupation: 'Chimney sweep'
+	},
+	{
+			name: 'Jane Doe',
+			age: 32,
+			role: 'Administrator'
+	},
+	{
+			name: 'Kate Müller',
+			age: 23,
+			occupation: 'Astronaut'
+	},
+	{
+			name: 'Bruce Willis',
+			age: 64,
+			role: 'World saver'
+	}
+];
+
+export function logPerson(person: Person) {
+	let additionalInformation: string;
+
+	if ('role' in person) {
+			additionalInformation = person.role;
+	} else {
+			additionalInformation = person.occupation;
+	}
+
+	console.log(` - ${person.name}, ${person.age}, ${additionalInformation}`);
+}
+
+persons.forEach(logPerson);

vinhnx/ex4.ts

@@ -0,0 +1,52 @@
+interface IUser {
+	type: 'user';
+	name: string;
+	age: number;
+	occupation: string;
+}
+
+interface IAdmin {
+	type: 'admin';
+	name: string;
+	age: number;
+	role: string;
+}
+
+export type TPerson = IUser | IAdmin;
+
+export const persons: TPerson[] = [
+	{ type: 'user', name: 'Max Mustermann', age: 25, occupation: 'Chimney sweep' },
+	{ type: 'admin', name: 'Jane Doe', age: 32, role: 'Administrator' },
+	{ type: 'user', name: 'Kate Müller', age: 23, occupation: 'Astronaut' },
+	{ type: 'admin', name: 'Bruce Willis', age: 64, role: 'World saver' }
+];
+
+export function isAdmin(person: TPerson) {
+	return person.type === 'admin';
+}
+
+export function isUser(person: TPerson) {
+	return person.type === 'user';
+}
+
+export function logPerson(person: TPerson) {
+	let additionalInformation: string = '';
+
+	if (isAdmin(person)) {
+			additionalInformation = (person as IAdmin).role;
+	}
+
+	if (isUser(person)) {
+			additionalInformation = (person as IUser).occupation;
+	}
+
+	console.log(` - ${person.name}, ${person.age}, ${additionalInformation}`);
+}
+
+console.log('Admins:');
+persons.filter(isAdmin).forEach(logPerson);
+
+console.log();
+
+console.log('Users:');
+persons.filter(isUser).forEach(logPerson);

vinhnx/ex5.ts

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+interface User {
+	type: 'user';
+	name: string;
+	age: number;
+	occupation: string;
+}
+
+interface Admin {
+	type: 'admin';
+	name: string;
+	age: number;
+	role: string;
+}
+
+export type Person = User | Admin;
+
+type TCriteria = {
+	[id in keyof User]?: User[keyof User];
+};
+
+export const persons: Person[] = [
+	{ type: 'user', name: 'Max Mustermann', age: 25, occupation: 'Chimney sweep' },
+	{
+			type: 'admin',
+			name: 'Jane Doe',
+			age: 32,
+			role: 'Administrator'
+	},
+	{
+			type: 'user',
+			name: 'Kate Müller',
+			age: 23,
+			occupation: 'Astronaut'
+	},
+	{
+			type: 'admin',
+			name: 'Bruce Willis',
+			age: 64,
+			role: 'World saver'
+	},
+	{
+			type: 'user',
+			name: 'Wilson',
+			age: 23,
+			occupation: 'Ball'
+	},
+	{
+			type: 'admin',
+			name: 'Agent Smith',
+			age: 23,
+			role: 'Administrator'
+	}
+];
+
+export const isAdmin = (person: Person): person is Admin => person.type === 'admin';
+export const isUser = (person: Person): person is User => person.type === 'user';
+
+export function logPerson(person: Person) {
+	let additionalInformation = '';
+	if (isAdmin(person)) {
+			additionalInformation = person.role;
+	}
+	if (isUser(person)) {
+			additionalInformation = person.occupation;
+	}
+	console.log(` - ${person.name}, ${person.age}, ${additionalInformation}`);
+}
+
+export function filterUsers(persons: Person[], criteria: TCriteria): User[] {
+	return persons.filter(isUser).filter((user) => {
+			const criteriaKeys = Object.keys(criteria) as (keyof User)[];
+
+			return criteriaKeys.every((fieldName) => {
+					return user[fieldName] === criteria[fieldName];
+			});
+	});
+}
+
+console.log('Users of age 23:');
+
+filterUsers(
+	persons,
+	{
+			age: 23
+	}
+).forEach(logPerson);

vinhnx/ex6.ts

@@ -0,0 +1,56 @@
+interface User {
+	type: 'user';
+	name: string;
+	age: number;
+	occupation: string;
+}
+
+interface Admin {
+	type: 'admin';
+	name: string;
+	age: number;
+	role: string;
+}
+
+export type Person = User | Admin;
+
+export const persons: Person[] = [
+	{ type: 'user', name: 'Max Mustermann', age: 25, occupation: 'Chimney sweep' },
+	{ type: 'admin', name: 'Jane Doe', age: 32, role: 'Administrator' },
+	{ type: 'user', name: 'Kate Müller', age: 23, occupation: 'Astronaut' },
+	{ type: 'admin', name: 'Bruce Willis', age: 64, role: 'World saver' },
+	{ type: 'user', name: 'Wilson', age: 23, occupation: 'Ball' },
+	{ type: 'admin', name: 'Agent Smith', age: 23, role: 'Anti-virus engineer' }
+];
+
+export function logPerson(person: Person) {
+	console.log(
+			` - ${person.name}, ${person.age}, ${person.type === 'admin' ? person.role : person.occupation}`
+	);
+}
+
+const getObjectKeys = <T>(obj: T) => Object.keys(obj as keyof T) as (keyof T)[];
+
+export function filterPersons(persons: Person[], personType: User['type'], criteria: Partial<Omit<User, 'type'>>): User[];
+export function filterPersons(persons: Person[], personType: Admin['type'], criteria: Partial<Omit<Admin, 'type'>>): Admin[];
+export function filterPersons(persons: Person[], personType: Person['type'], criteria: Partial<Person>): Person[] {
+	return persons
+			.filter((person) => person.type === personType)
+			.filter((person) => {
+					let criteriaKeys = getObjectKeys(criteria);
+					return criteriaKeys.every((fieldName) => {
+							return person[fieldName] === criteria[fieldName];
+					});
+			});
+}
+
+export const usersOfAge23 = filterPersons(persons, 'user', { age: 23 });
+export const adminsOfAge23 = filterPersons(persons, 'admin', { age: 23 });
+
+console.log('Users of age 23:');
+usersOfAge23.forEach(logPerson);
+
+console.log();
+
+console.log('Admins of age 23:');
+adminsOfAge23.forEach(logPerson);