javascript - 有没有更好的方法在JavaScript中执行可选的函数参数？ [重复](Is there a better way to do optional function parameters in JavaScript? [duplicate])

Question

This question already has an answer here:

(这个问题在这里已有答案：)

• Set a default parameter value for a JavaScript function 24 answers

  (为JavaScript函数设置 24个答案 的默认参数值)

I've always handled optional parameters in JavaScript like this:

(我总是在JavaScript中处理可选参数，如下所示：)

function myFunc(requiredArg, optionalArg){
  optionalArg = optionalArg || 'defaultValue';

  // Do stuff
}

Is there a better way to do it?

(有没有更好的方法呢？)

Are there any cases where using ||

(有没有使用||)

like that is going to fail?

(那会失败吗？)

  ask by Mark Biek translate from so

Answer 1

Your logic fails if optionalArg is passed, but evaluates as false - try this as an alternative

(如果传递了OptionalArg，您的逻辑将失败，但计算结果为false - 请尝试将此作为替代方法)

if (typeof optionalArg === 'undefined') { optionalArg = 'default'; }

Or an alternative idiom:

(或另类成语：)

optionalArg = (typeof optionalArg === 'undefined') ? 'default' : optionalArg;

Use whichever idiom communicates the intent best to you!

(使用哪个成语最能传达您的意图！)