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Ternary Operator

mrcount profile image mrCount ・2 min read

Came across it when traversing the sea of JS. I don't know why, but it looks so elegant. And I like it so much I've decided to write about it.

tl:dr version: Basically it's a substitute for the "if" statement.

The premise

The passage bellow is a straight copy from the MDN website.

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. This operator is frequently used as a shortcut for the if statement.

This means, you can write an entire "if" statement using just ":" and "?".

Example

Let's say we're asking a user to input his name with prompt, and then we would like to print out his name with a "greeting". If the user doesn't input anything, we will assign a default value.

if statement

const userName = prompt("Gief me your name!!");
const userGreeting = " waddles around like recieving a prostate exam";

if (userName === "") {
    const userNameDefault = "Yo'momma";
    console.log(userNameDefault + userGreeting);
} else {
    console.log(userName + userGreeting);
} 

ternary operator

const userName = prompt("Gief me your name!!");
const userGreeting = " waddles around like recieving a prostate exam";

userName === ""
    ? (userName = "Yo'daddy") + console.log(userName + userGreeting)
    : console.log(userName + userGreeting);

ternary operator with template literal

const userName = prompt("Gief me your name!!");
const userGreeting = `${userName} waddles around like recieving a prostate exam`;

userName === ""
    ? (userName = "Yo'daddy") + console.log(userGreeting)
    : console.log(userGreeting);

What the MDN files don't mention if you have more expressions to execute. You can simply chain them together with '+'.

Conclusion

As you see, the code is shorter and looks a little easier to read once you've got used to it.

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mrcount profile

mrCount

@mrcount

I like to learn, newbie at web development, coach, combat sports, if i'm not busy, i'm idling with a smile on my face.

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