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javascriptjquery-pluginsexpressionconditional-statementsternary

How do I turn this conditional logic into a ternary expression?

Here is small little jquery plugin that checks if the element passed in is an input element and if it is empty:

$.fn.inputIsEmpty = function() {
    if (!this.is('input:text')) {
        return false;
    } else {
        return $.trim($(this).val()).length == 0;
    }
};

The above logic works. So I tried turning this into a sweetened ternary expression:

$.fn.inputIsEmpty = function() {
    this.is('input:text') ? $.trim($(this).val()).length == 0 : false;
};

But it just returns undefined - what am I doing wrong?

Solution

  • I would make use of operator short circuiting:

    return this.is('input:text') && $.trim(this.val()).length === 0;

    If this.is('input:text') is false, the second part won't need to be evaluated, as false && any boolean will be false regardless of the other boolean's value. It acts like your if statement.