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I was going through some stuff in the jQuery source, specifically the inArray method and I found this line of code:
i = i ? i < 0 ? Math.max( 0, len + i ) : i : 0;
What I am seeing is two ternary operators, but I have no idea how this is used. I understand how the ternary operator works, but I have never seen it used like this before. How does this piece of code work??
708
For example, you should not try to make ternary operators nested inside of ternary operators.
A Ternary Operator in Javascript is a special operator which accepts three operands. It is also known as the "conditional" or "inline-if" operator. Ternary Operator in Javascript makes our code clean and simpler. It can be chained like an if-else if....else if-else block.
You can nest one ternary operator as an expression inside another ternary operator to work as a Nested ternary operator in JavaScript.
The conditional (ternary) operator is the only JavaScript operator that takes three operands: a condition followed by a question mark ( ? ), then an expression to execute if the condition is truthy followed by a colon ( : ), and finally the expression to execute if the condition is falsy.
Just break it down like you would 1 + 2 + 3:
if (i) {
if (i < 0) {
i = Math.max(0, len + i);
} else {
i = i; // no-op
}
} else {
i = 0; // also no-op, since if `i` were anything else it would be truthy.
}
In fact, that whole line seems inefficient to me. Personally I'd just use:
if (i < 0) {
i = Math.max(0, len + i);
}
i = i ? i < 0 ? Math.max( 0, len + i ) : i : 0;
Breaks down to:
var i;
if(i){
if(i<0){
i = Math.max(0, len + i);
}else{
i = i;
}
}else{
i = 0;
}
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