函数中的三元运算符

Question

I'm new to ternary operators. I have the following function. I'm trying to understand what's going on:

function toProperHex(hex) {
    hex = hex.toLowerCase();
    return hex ? hex != 'ffffff' ? '#' + hex : '#eee' : '#000';
}

I know that whatever is before the ? is the condition and what comes after is the value that the variable becomes if the condition is true, and after the colon, will be what the cariable becomes if the condition is not true. Now there are two conditions apparently and three possible outcomes. Is this an if / else if statement with a Ternary structure. Clarification would be greatly appreciated.

Thanks!

Answer 1

This is two ternary operators on one line. It's equivalent to this:

if(hex) {
    if(hex != 'ffffff') {
        return '#' + hex;
    } else {
        return '#eee';
    }
} else {
    return '#000';
}

I think two ternaries on one line is a bad idea, makes them hard to read. You can basically divide it up like this

return hex ? (hex != 'ffffff' ? '#' + hex : '#eee') : '#000';

The parentheses help show the inner ternary.