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！)