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Javascript code:
var a = (b) ? b : 40;
It is working, just NetBeans says: "Use the || operator (Column [where the ? is])". I didn't find any explanation.
What is it?
Thanks!
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The logical OR ( || ) operator (logical disjunction) for a set of operands is true if and only if one or more of its operands is true. It is typically used with boolean (logical) values. When it is, it returns a Boolean value.
The bitwise OR assignment operator ( |= ) uses the binary representation of both operands, does a bitwise OR operation on them and assigns the result to the variable.
The ! symbol is used to indicate whether the expression defined is false or not. For example, !( 5==4) would return true , since 5 is not equal to 4. The equivalent in English would be not .
So, what is the meaning of {} in JavaScript? In JavaScript, we use {} braces for creating an empty object. You can think of this as the basis for other object types. Object provides the last link in the prototype chain that can be used by all other objects, such as an Array.
If you are just testing for the truthyness of b then you can do this:
var a = b || 40;
… which is shorter and (arguably) more obvious. In JavaScript, || is a short circuit operator. It returns the left hand side if it is true, otherwise it returns the right hand side. (i.e. it doesn't return a boolean unless the input was a boolean).
If you want to see if b is actually defined, then you are better off with:
var a = (typeof b !== "undefined") ? b : 40;
The pipes are the or statement. var a = b || 40 says if b is non-falsey value, let a=b, otherwise 40.
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