Evaluate boolean expression from a variable in JavaScript

Question

I have some Variables that have like a key word and then an identifier and I'm trying to evaluate this expression.

Example:

$day = today; //Assume it is Monday
$.each(responseAdvertiser, function(index, value) {
    var hasMonday = value.hasMonday;     //TRUE OR FALSE
    var hasTuesday = value.hasTuesday;   //TRUE OR FALSE

    //Whar I'm trying to do:
    var has="has";
    var img="img";
    var txt="txt";
    var day = $day.toLowerCase();  //monday
    var hasDay = has+day;          //hasmonday

    if (hasDay == true){          // TRYING TO EVALUATE THIS
        var dayImg= day+img;          //mondayimg
        var dayTxt = day+txt;         //mondaytxt

        var todayImg = value.dayImg;
        var todayTxt = value.dayTxt;
    // I know how to make this work in PHP using variable variables, like
    // $x = hello
    // $hello = buddy
    // echo $$x   #PRINTS buddy
    }
}

I am trying to evaluate hasmonday, but since I'm using the variable "hasDay" which is just a string named "hasmonday" it doesn't really evaluate the way I need to.

Hope I made myself clear, if not, comment and I'll try to explain it better. Thanks in advance.

you are comparing a string to boolean, it should always return false — davidhu
– davidhu, Commented Aug 29, 2016 at 23:31
The problem is that it's not just hasmonday, but I have hastuesday, haswednesday, etc... And I need to evaluate all of this days according to today's weekday — HiGonz
– HiGonz, Commented Aug 29, 2016 at 23:36
No, it's isn't clear what you are try to do. Try restating it a bit. — Michael Lorton
– Michael Lorton, Commented Aug 29, 2016 at 23:36

ryan · Accepted Answer · 2016-08-29 23:38:27Z

1

To access a property by name, use the brackets notation.

So for your example, you could get the boolean value by

var hasDay = "hasMonday";
var b = value[hasDay]; // equivalent to 'var b = value.hasMonday;'
if (b) {
    // code here
}

answered Aug 29, 2016 at 23:38

ryan

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