CODEWITHSUNDEEP
javascript
rjsandman18
rjsandman18

Reputation: 123

What is the Purpose of a "?" in Javascript?

What purpose does the question mark serve in the following code snippet:

Template.lists.selected = function () {
    return Session.equals('list_id', this._id) ? 'selected' : '';
};

Upvotes: 1

Views: 283

Answers (1)

EmmyS
EmmyS

Reputation: 12138

It's known as a ternary operator in a number of languages. It's a shortcut for a full-on if-then statement.

Instead of writing this:

Template.lists.selected = function () {
   if(Session.equals('list_id', this._id)) {
      return 'selected';
   }
   else {
      return '';
   }
};

You do this:

Template.lists.selected = function () {
   return Session.equals('list_id', this._id) ? 'selected' : '';
};

The if return is immediately after the question mark; the else return is after the colon.

Upvotes: 6

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