javascript测试长度

Question

If I have an object MyObject that contains an array of objects ListOfOtherObjects and I write this:

   if (MyObject.ListOfOtherObjects.length !== 0) {...}

to test and see if the array contains OtherObjects, is it the same as writing this:

   if (MyObject.ListOfOtherObjects) {...}

Thanks.

Answer 1

Nope, you need to check the length property. An Array is always truthy , like any other Object .

You can, however, omit the explicit check of !== 0 .

if (MyObject.ListOfOtherObjects.length) {...}

This condition will be true if the Array has at least one element.