What 'something' ? 'something' : 'something' operator means?

Question

I found some code from https://github.com/andrewgodwin

    var ws_scheme = window.location.protocol == "https:" ? "wss" : "ws";

What does 'something' ? 'something' : 'something' means?

`?:` is the ternary operator. It is a short and often gorgeous method of writing a simple `if` statement in many languages. — jdgregson, Feb 10 '18 at 07:22

score 2 · Answer 1 · answered Feb 10 '18 at 07:19

2

It is conditional operator in javascript ref. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

answered Feb 10 '18 at 07:19

programtreasures

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score 2 · Answer 2 · answered Feb 10 '18 at 07:20

2

var ws_scheme = window.location.protocol == "https:" ? "wss" : "ws";

that means:

var ws_scheme;
if (window.location.protocol == "https:") {
    ws_scheme = "wss";
} else {
    ws_scheme = "ws";
}

answered Feb 10 '18 at 07:20

xianshenglu

4,009
1
10
25

score 2 · Accepted Answer · answered Feb 10 '18 at 07:21

It's called conditional (ternary) operator. This operator is frequently used as a shortcut for the if statement. If the condition before the "?" is true then the value just after the "?" is assigned to the variable, else the value after ":" is assigned to the variable.

Details at: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

What 'something' ? 'something' : 'something' operator means?

3 Answers3