TypeScript是目前不得不学的内容
- Ts的货色其实十分十分的多，上到
tsconfig的配置，下到写法，内容。 - Ts正在疯狂的迭代，进入
4.0版本行将，外面的内容十分十分的多，能够说，入门很简略，然而要写精通，真的还是要花很多功夫。 - 本文一共分上、下集,欢送你关注我的公众号：【
前端巅峰】,前端、后端、源码、架构、算法、面试都有,更有理财，心理学、开源我的项目等日常分享。
正式开始
- 第一题,根本
interface应用考查,定义一个item接口，合乎应用
interface item { name: string; age: number; occupation: string;}const users: item[] = [ { name: 'Max Mustermann', age: 25, occupation: 'Chimney sweep', }, { name: 'Kate Müller', age: 23, occupation: 'Astronaut', },];function logPerson(user: item) { console.log(` - ${chalk.green(user.name)}, ${user.age}`);}console.log(chalk.yellow('Users:'));users.forEach(logPerson);
- 第二题,考查联结类型,让
logPerson函数不报错
interface User { name: string; age: number; occupation: string;}interface Admin { name: string; age: number; role: string;}type Person = User | Admin;const persons: Person[] /* <- 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', },];function logPerson(user: Person) { console.log(` - ${chalk.green(user.name)}, ${user.age}`);}persons.forEach(logPerson);
- 第三题,类型推断、联结类型、类型断言（此题我感觉不是最优解法,欢送大家指出）,让
logPerson不报错
interface User { name: string; age: number; occupation: string;}interface Admin { name: string; age: number; role: string;}type Person = User | Admin;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', },];function logPerson(person: Person) { let additionalInformation: string; if ((person as Admin).role) { additionalInformation = (person as Admin).role; } else { additionalInformation = (person as User).occupation; } console.log( ` - ${chalk.green(person.name)}, ${person.age}, ${additionalInformation}` );}persons.forEach(logPerson);
- 第四题，我这里同样应用了类型断言和类型推断、联结类型解题（感觉也不是最优），让
logPerson不报错
interface User { type: 'user'; name: string; age: number; occupation: string;}interface Admin { type: 'admin'; name: string; age: number; role: string;}type Person = User | Admin;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' },];function isAdmin(person: Person) { return person.type === 'admin';}function isUser(person: Person) { return person.type === 'user';}function logPerson(person: Person) { let additionalInformation: string = ''; if (isAdmin(person)) { additionalInformation = (person as Admin).role; } if (isUser(person)) { additionalInformation = (person as User).occupation; } console.log( ` - ${chalk.green(person.name)}, ${person.age}, ${additionalInformation}` );}console.log(chalk.yellow('Admins:'));persons.filter(isAdmin).forEach(logPerson);console.log();console.log(chalk.yellow('Users:'));persons.filter(isUser).forEach(logPerson);
- 第五题,我应用了索引签名解题,保障
filterUsers函数不报错
interface User { type: 'user'; name: string; age: number; occupation: string;}interface Admin { type: 'admin'; name: string; age: number; role: string;}type Person = User | Admin;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', },];const isAdmin = (person: Person): person is Admin => person.type === 'admin';const isUser = (person: Person): person is User => person.type === 'user';function logPerson(person: Person) { let additionalInformation: string = ''; if (isAdmin(person)) { additionalInformation = person.role; } if (isUser(person)) { additionalInformation = person.occupation; } console.log( ` - ${chalk.green(person.name)}, ${person.age}, ${additionalInformation}` );}function filterUsers( persons: Person[], criteria: { age: number; [index: string]: number }): User[] { return persons.filter(isUser).filter((user) => { let criteriaKeys = Object.keys(criteria) as (keyof User)[]; return criteriaKeys.every((fieldName) => { return user[fieldName] === criteria[fieldName]; }); });}console.log(chalk.yellow('Users of age 23:'));filterUsers(persons, { age: 23,}).forEach(logPerson);
- 第六题，考查
overloads,我对filterPersons独自进行了解决，解题，保障logPerson函数能够返回不同的类型数据
interface User { type: 'user'; name: string; age: number; occupation: string;}interface Admin { type: 'admin'; name: string; age: number; role: string;}type Person = User | Admin;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' },];function logPerson(person: Person) { console.log( ` - ${chalk.green(person.name)}, ${person.age}, ${ person.type === 'admin' ? person.role : person.occupation }` );}function filterPersons( persons: Person[], personType: 'user', criteria: { [fieldName: string]: number }): User[];function filterPersons( persons: Person[], personType: 'admin', criteria: { [fieldName: string]: number }): Admin[];function filterPersons( persons: Person[], personType: string, criteria: { [fieldName: string]: number }) { return persons .filter((person) => person.type === personType) .filter((person) => { let criteriaKeys = Object.keys(criteria) as (keyof Person)[]; return criteriaKeys.every((fieldName) => { return person[fieldName] === criteria[fieldName]; }); });}let usersOfAge23: User[] = filterPersons(persons, 'user', { age: 23 });let adminsOfAge23: Admin[] = filterPersons(persons, 'admin', { age: 23 });console.log(chalk.yellow('Users of age 23:'));usersOfAge23.forEach(logPerson);console.log();console.log(chalk.yellow('Admins of age 23:'));adminsOfAge23.forEach(logPerson);
- 第七题,考查泛型应用，依据传入参数不同,动静返回不同类型的数据,保障
swap函数运行失常
interface User { type: 'user'; name: string; age: number; occupation: string;}interface Admin { type: 'admin'; name: string; age: number; role: string;}function logUser(user: User) { const pos = users.indexOf(user) + 1; console.log( ` - #${pos} User: ${chalk.green(user.name)}, ${user.age}, ${ user.occupation }` );}function logAdmin(admin: Admin) { const pos = admins.indexOf(admin) + 1; console.log( ` - #${pos} Admin: ${chalk.green(admin.name)}, ${admin.age}, ${admin.role}` );}const admins: Admin[] = [ { type: 'admin', name: 'Will Bruces', age: 30, role: 'Overseer', }, { type: 'admin', name: 'Steve', age: 40, role: 'Steve', },];const users: User[] = [ { type: 'user', name: 'Moses', age: 70, occupation: 'Desert guide', }, { type: 'user', name: 'Superman', age: 28, occupation: 'Ordinary person', },];function swap<T, L>(v1: T, v2: L): [L, T] { return [v2, v1];}function test1() { console.log(chalk.yellow('test1:')); const [secondUser, firstAdmin] = swap(admins[0], users[1]); logUser(secondUser); logAdmin(firstAdmin);}function test2() { console.log(chalk.yellow('test2:')); const [secondAdmin, firstUser] = swap(users[0], admins[1]); logAdmin(secondAdmin); logUser(firstUser);}function test3() { console.log(chalk.yellow('test3:')); const [secondUser, firstUser] = swap(users[0], users[1]); logUser(secondUser); logUser(firstUser);}function test4() { console.log(chalk.yellow('test4:')); const [firstAdmin, secondAdmin] = swap(admins[1], admins[0]); logAdmin(firstAdmin); logAdmin(secondAdmin);}function test5() { console.log(chalk.yellow('test5:')); const [stringValue, numericValue] = swap(123, 'Hello World'); console.log(` - String: ${stringValue}`); console.log(` - Numeric: ${numericValue}`);}[test1, test2, test3, test4, test5].forEach((test) => test());
- 第八题，考查
Omit和多类型&的应用，应用Omit提取type字段，最小代价实现了这道题
interface User { type: 'user'; name: string; age: number; occupation: string;}interface Admin { type: 'admin'; name: string; age: number; role: string;}type Person = User | Admin | PowerUser;const persons: Person[] = [ { type: 'user', name: 'Max Mustermann', age: 25, occupation: 'Chimney sweep' }, { type: 'admin', name: 'Jane Doe', age: 32, role: 'Administrator' }, { type: 'user', name: 'Kate Müller', age: 23, occupation: 'Astronaut' }, { type: 'admin', name: 'Bruce Willis', age: 64, role: 'World saver' }, { type: 'powerUser', name: 'Nikki Stone', age: 45, role: 'Moderator', occupation: 'Cat groomer' }];type PowerUser = Omit<User, 'type'> & Omit<Admin, 'type'> & {type: 'powerUser'};function isAdmin(person: Person): person is Admin { return person.type === 'admin';}function isUser(person: Person): person is User { return person.type === 'user';}function isPowerUser(person: Person): person is PowerUser { return person.type === 'powerUser';}function logPerson(person: Person) { let additionalInformation: string = ''; if (isAdmin(person)) { additionalInformation = person.role; } if (isUser(person)) { additionalInformation = person.occupation; } if (isPowerUser(person)) { additionalInformation = `${person.role}, ${person.occupation}`; } console.log(`${chalk.green(person.name)}, ${person.age}, ${additionalInformation}`);}console.log(chalk.yellow('Admins:'));persons.filter(isAdmin).forEach(logPerson);console.log();console.log(chalk.yellow('Users:'));persons.filter(isUser).forEach(logPerson);console.log();console.log(chalk.yellow('Power users:'));persons.filter(isPowerUser).forEach(logPerson);
写给读者
- 后面八道题并不一定是最优解法,
Ts外面货色的确多，如果你有好的解法能够公众号后盾私信我 - 前面会补充剩下的题目，由易到难
- 不定期补充前端架构师面试题、各种技术的系列学习题目
- 我是
Peter酱，架构设计过20万人端到端加密超级群性能的桌面IM软件,我微信:CALASFxiaotan,不闲聊 - 另外欢送珍藏我的材料网站:
前端生存社区:https://qianduan.life,能够右下角点个在看，关注一波公众号:[前端巅峰]