你可以理解TS是JS的的一个超集,通过编译成纯js来在浏览器等上都可以使用。 相对于js而言,ts是一个强类型语言。二者之间的区别是TypeScript是静态类型,js是动态类型(详见强类型、弱类型、静态类型、动态类型的区别)。 弱类型语言(js)是据类型可以被忽略的语言。它与强类型定义语言相反, 一个变量可以赋不同数据类...
private 和 protected。 public: 默认的修饰符,它表示属性或方法是公有的,可以在类的内部和外部被访问。 private: 表示属性或方法是私有的,只能在类的内部被访问,外部无法访问。 protected: 表示属性或方法是受保护的,只能在类的内部及其子类中被访问,外部无法访问。 1.private 修饰符 示例: classPerson{privatenam...
Switch Statement This example demonstrates how to use aswitchstatement to handle multiple cases. switch_statement.ts let day: number = 3; let dayName: string; switch (day) { case 1: dayName = "Monday"; break; case 2: dayName = "Tuesday"; break; case 3: dayName = "Wednesday"; break;...
*/ // "noImplicitReturns": true, /* Enable error reporting for codepaths that do not explicitly return in a function. */ // "noFallthroughCasesInSwitch": true, /* Enable error reporting for fallthrough cases in switch statements. */ // "noUncheckedIndexedAccess": true, /* Add 'undef...
switch (ch) { case CharacterCodes.lineFeed: case CharacterCodes.carriageReturn: precedingLineBreak = true; if (skipTrivia) { pos++; continue; } else { if (ch === CharacterCodes.carriageReturn && pos + 1 < end && text.charCodeAt(pos + 1) === CharacterCodes.lineFeed) { ...
const reducer = (state, action) => {switch (action.type) {case 'increment':return {count: state.count + 1};case 'decrement':return {count: state.count - 1};default:throw new Error();}}const Counter = () => {const initialState = {count: 0}const [state, dispatch] = useReducer(...
switch (data.name) { case 'a': { console.log(data.age) break } case 'b': { console.log(data.surname) break } case 'c': { console.log(data.height) break } } } Functions TypeScript also adds some new capabilities to the standard JavaScript functions to make them easier to work wi...
*/ // "noFallthroughCasesInSwitch": true, /* Enable error reporting for fallthrough cases in switch statements. */ // "noUncheckedIndexedAccess": true, /* Add 'undefined' to a type when accessed using an index. */ // "noImplicitOverride": true, /* Ensure overriding members in ...
switch (item.type) { case SR_BLOCK_LAYOUT_STRONG: { NSHashTable *objects = [item objectsForBeginAddress:begin]; SRAddObjectsFromHashTable(references, objects); begin += item.count; } break; case SR_BLOCK_LAYOUT_BYREF: { for (int i = 0; i < item.count; i++, begin++) { ...
ReactElement是一个接口,包含type,props,key三个属性值。该类型的变量值只能是两种:null 和 ReactElement实例。 通常情况下,函数组件返回ReactElement(JXS.Element)的值。 3. React.ReactNode ReactNode类型的声明如下: 复制 type ReactText=string|number;type ReactChild=ReactElement|ReactText;interface ReactNodeAr...