functionfn1(param1, param2 = 'default value') { console.log(arguments.length); console.log(arguments[0]); } 在ES6 过后, 大部分人会用 rest parameters 取代 arguments 对象. 函数是一等公民 函数可以 assign to variables, 也可以当参数传来传去. functionmethod1(method2) {} const method2=functi...
arg1, ... argN(optional) - Arguments for the functionfunc. Note:By default, in a functionthisrefers to the global object i.e, window in web browsers andglobalin node.js. call() Return Values Returns the result obtained from calling the function with the specifiedthisvalue and arguments. N...
你可以用 arguments.length 来获得实际传递给函数的参数的数量,然后用 arguments 对象来访问每个参数。 例如,考虑有一个用来连接字符串的函数。唯一正式的参数是在连接后的字符串中用来分隔各个连接部分的字符。该函数定义如下: jsCopy to Clipboard function myConcat(separator) { let result = ""; // 初始化...
functionf(x, y, z) {// 首先,验证传入实参的个数是否正确if(arguments.length!=3) {thrownewError("function f called with "+arguments.length+"arguments, but it expects 3 arguments."); }// 再执行函数的其他逻辑}f(1,2);// Uncaught Error: function f called with 2arguments, but it expects...
The calc function takes two argument in the first function call, and the index parameter is set as 2. For the second function call, we pass all three parameters, and therefore, the index parameter becomes what we pass, 3. Using arguments.length property for optional parameters In another app...
a*b;}var result = multiply(a, b);console.log('答案是 - ' + result);function multiply ...
argsArray(optional) - An array containing the arguments to the function. apply() Return Value Returns the result of the called function with the specifiedthisvalue and arguments. Example 1: apply() Method to call a Function // object definitionconstpersonName = {firstName:"Taylor",lastName:"...
functionfoo(param1,param2){...} Argumentsare used to invoke a function.They are also called actual parameters and actual arguments. In the following example,3and7are arguments: foo(3,7); Defining Functions This section describes three ways tocreate a function: ...
A higher-order function adheres to a very specific definition: It’s first-class (refer back to Chapter 2 if you need a refresher on this topic) Takes a function as an argument Returns a function as a result I’ve already shown many functions that take other functions as arguments, but...
Pass data to a .NET method when calling the invokeMethodAsync function by passing the data as arguments.To demonstrate passing data to .NET, pass a starting position to the ReturnArrayAsync method where the method is invoked in JS:JavaScript Copy export function returnArrayAsync() { Dot...