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GitHub仓库：基础类型

Number

  1. /* 数字类型
  2. -------------------------- */
  3. const binaryNumber: number = 0b1010
  4. const octalNumber: number = 0o1721
  5. const decimalNumber: number = 45
  6. const hexNumber: number = 0x1e3c

String

  1. /* 字符串类型
  2. -------------------------- */
  3. const string: string = '123Hello'

Boolean

  1. /* 布尔类型
  2. -------------------------- */
  3. const success: boolean = true
  4. const faile: boolean = false

Array

  1. /* 数组类型
  2. -------------------------- */
  3. const numberArr: number[] = [2333]
  4. const stringArr: string[] = ['Apple', 'Banana']
  5. /* 使用数组泛型
  6. -------------------------- */
  7. const otherNameArr: Array<number> = [1, 2, 3]
  9. const doubleTypeArr: (string | number)[] = [123, 'Apple']

Object

  1. /* object 类型
  2. -------------------------- */
  3. let obj = {
  4.   name: 'chara'
  5. }
  7. let obj2 = obj
  8. obj2.name = 'C'
  9. console.log(obj);
  11. function getObject(obj: object): void {
  12.   console.log(obj)
  13. }
  15. getObject(obj2)

Any

  1. /* any 类型
  2. -------------------------- */
  3. let anyValue: any = 123
  5. anyValue = 'abc'
  6. anyValue = false
  8. const anyArr: any[] = [1, 'a']

Undefined

  1. /* undefined 类型，是其他类型的子类型
  2. -------------------------- */
  3. const u: undefined = undefined

Null

  1. /* null 类型，是其他类型的子类型
  2. -------------------------- */
  3. const n: null = null

Never

  1. /* never 类型
  2. -------------------------- */
  3. const errorMessage = (message: string): never => {
  4.   throw new Error(message)
  5. }
  7. const infiniteFunc = (): never => {
  8.   while(true) {}
  9. }
  11. /* never 类型是任何类型的子类型，可以赋值给任何类型
  12. -------------------------- */
  13. const neverVariable = (() => {
  14.   while(true) {}
  15. })()
  17. let num: number = 5
  18. num = neverVariable
  20. /* 没有类型是 never 的子类型或可以赋值给 never 类型（除了 never 本身）
  21.  * 即使 any 类型也不可以赋值给 never 类型
  22. -------------------------- */

Enum

  1. /* 枚举类型
  2. -------------------------- */
  3. enum Roles {
  4.   SUPER_ADMIN,
  5.   ADMIN = 4,
  6.   USER
  7. }
  9. console.log(Roles.SUPER_ADMIN)
  11. console.log(Roles[4])

Tuple

  1. /* 元组类型
  2. -------------------------- */
  3. const tuple: [string, number, boolean] = ['a', 1, true]

Void

  1. /* void 类型
  2. -------------------------- */
  3. const consoleText = (text: string): void => {
  4.   console.log(text)
  5. }
  7. // void 类型的变量可以赋值为 undefined 和 null
  8. let voidVal = undefined
  9. voidVal = null

Type Assertion

  1. /* 类型断言
  2. -------------------------- */
  3. const getLength = (target: string | number): number => {
  4.   if((<string>target).length || (target as string).length === 0) {
  5.     return (<string>target).length
  6.   } else {
  7.     return target.toString().length
  8.   }
  9. }
  11. getLength(123)
  12. getLength('Apple')
  14. /* 可以使用自定义类型保护来简化
  15. -------------------------- */