I have a function in a class
MyClass.prototype.IsFriend = function(){
return (this.m_Object1 && !this.m_Object1.m_ABoolean && this.m_Object2);
};
m_Object1 is an object in MyClass.
m_ABoolean is a boolean within m_Object1, true or false.
m_Object2 is another object in MyClass.
When this function should be returning false when m_Object1 is null OR m_ABoolean is true OR m_Object2 is null, it returns null instead.
Note: m_Object1, m_ABoolean and m_Object2 are never undefined.
Why?
The && operator return the first falsy value (the operand itself) it encounters, if it encounters null it will return null -> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_AND
Logical operators in javascript return the first logically determined value from left to right,
For instance, && operator returns the first value if it's falsy or the second one if not.
This answer is a good read and the MDN Documentation is a good reference.
I think that some of your values are null since:
true && null === null
Don't you have a way to check with debugger or with console.log the output of these values?