如何处理JavaScript条件语句中的可为空的对象

Question

I have a variable that can either be set to false or to an object xyz .

I want to do something like this:

if (var1) {
  if (var1.x.y.z === 1) {
    // do stuff
  }
} else {
  // do something if var1 OR var1.x.y.z === 1 is false
}

I'm having trouble setting up this conditional statement without having to duplicate the else code for the outer if statement and the inner if statement.

Answer 1

Try using !!, this evaluates whatever the variable is as truthy or falsy. Basically if var1 is not not false, thus true. If var1 is anything but literally false then "do stuff".

Edited.. you can add the second test inline.

if (!!var1 && var1.x.y.z === 1) {
    // do stuff
} else {
   // do other stuff
}