array.length与array.length> 0

问题描述：

检查数组的长度是否为真实值与检查数组的长度是否大于0之间有什么区别?

Is there any difference between checking an array's length as a truthy value vs checking that it's > 0?

换句话说，有任何理由要使用其中一项而不是另一项:

In other words is there any reason to use one of these statements over the other:

var arr = [1,2,3];
if (arr.length) {
}

if (arr.length > 0) {
}

答

array.length最快，并且比array.length > 0短.您可以看到它们的速度差异: http://jsperf.com/test-of-array-长度

array.length is fastest and shorter than array.length > 0. You can see difference of their speeds : http://jsperf.com/test-of-array-length

if(array.length){...}与if(0){...}或if(false){...}