import * as ts from 'typescript'; function getFunctionParameterTypes(sourceCode: string, functionName: string): ts.Type[] { const sourceFile = ts.createSourceFile('temp.ts', sourceCode, ts.ScriptTarget.Latest); const parameterTypes: ts.Type[] = []; function visit(node: ts.Node)...
超类型 getAnimalName 和子类型 getDogName 的方法可以相互分配。如果 strictFunctionTypes 设置为 true,则 Typescript 的参数进行逆变比较。 <pre class="prettyprint hljs typescript" style="padding: 0.5em; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; color: rgb(68, 68, 68); b...
function multiply(a: number, b: number) { return a * b; } Try it Yourself » If no parameter type is defined, TypeScript will default to using any, unless additional type information is available as shown in the Default Parameters and Type Alias sections below.Optional...
When implementing a function, it doesn't have to pay attention to everything that has been passed in. In each function call above, we pass the correct parameters, but the function does not necessarily use them. It can choose to ignore all parameters or pay attention to just the event, or...
If a default-initialized parameter comes before a required parameter, users need to explicitly pass undefined to get the default initialized value. 代码语言:javascript 代码运行次数:0 运行 AI代码解释 function buildName(firstName: string, lastName = "Smith") { // ... } 2.1.4. Rest Parameter...
expression, we can use the “infer” keyword to either get the type of the elements of an array, or even to get the return type of a function. We can use this to build a “FnReturnType” type, that will give us the return type of the function passed in as the generic parameter....
// automatic constructor parameter assignment constructor(public fname: string, public lname: string) { }}function logProgrammer<T extends Programmer>(prog: T): void { console.log(`${ prog.fname} ${prog.lname}` );}const programmer = new Programmer("Ross", "Bulat");log...
function getUserFullName(user: User, prefix?: string) {return `${prefix ?? ''}${user.firstName} ${user.lastName}`;} 在此代码块的第一个突出显示部分中,我们正在向函数添加一个可选的前缀参数,在第二个突出显示部分中,我们将使用它作为用户全名的前缀。为...
function isFish(pet: Fish | Bird): pet is Fish { return (<Fish>pet).swim !== undefined; } 1. 2. 3. 在这个例子里,pet is Fish就是类型谓词。谓词为parameterName is Type这种形式,parameterName必须是来自于当前函数签名里的一个参数名。 每当使用一些变量调用isFish时,TypeScript会将变量缩减为那...
const getter = function (this: any) { const currVal = this[backingField]; console.log(`Get: ${key} => ${currVal}`); return currVal; }; // property setter const setter = function (this: any, newVal: any) { console.log(`Set: ${key} => ${newVal}`); ...