CODEWITHSUNDEEP
javascriptjqueryknockout.js
user1405195
user1405195

Reputation: 1681

Evaluate value of observable as a variable rather than a string

How do I amend responseText: self.registrationmark so that the value of self.registrationmark evaluates to a variable rather than a string?

e.g. If the value of self.registrationmark is DE63BEY then responseText: should evaluate to the variable DE63BEY

HTML

<input type="text" id="registrationmark" data-bind="value: registrationmark">

Javascript

function ViewModel() {
    var self = this;

    self.registrationmark = ko.observable();

    var DE63BEY = { ... }
    var SL64KWX = { ... }
    var CU56OHG = { ... }
    var VN10YMY = { ... }   
    var Y926MNB = { ... }

    $.mockjax({
        url: '/test',
        dataType: 'json',
        responseTime: 2500,
        responseText: self.registrationmark
    });

    ...

}

ko.applyBindings(new ViewModel());

Upvotes: 0

Views: 181

Answers (3)

Michael Best
Michael Best

Reputation: 16688

As @sifriday describes, you can define your "variables" as properties of an object, which can be looked up by name. They don't necessarily have to be defined in self. It can be a separate object:

var responses = {
    DE63BEY: { ... },
    SL64KWX: { ... },
    CU56OHG: { ... },
    VN10YMY: { ... },
    Y926MNB: { ... }
};

Then

responseText: responses[self.registrationmark()]

If for some reason, you need to define the values as variables, you can use eval to read their values dynamically. This method is potentially unsafe and shouldn't be used.

responseText: eval(self.registrationmark())

Upvotes: 1

sifriday
sifriday

Reputation: 4482

Having just read your comment to Matthew above, I think you first need to set the scope of the variables to this/self:

self.DE63BEY = { ... }
self.SL64KWX = { ... }
self.CU56OHG = { ... }
self.VN10YMY = { ... }   
self.Y926MNB = { ... }

Then you must be after:

responseText: self[self.registrationmark()]

ie, call 

self.registrationmark()

to get a string like "DE63BEY" and then to get the corresponding variable, you need to look it up within self, as if you were doing:

self["DE63BEY"]

which is of course equivalent to

self.DE63BEY

which is the variable you're after!

Upvotes: 2

Matthew James Davis
Matthew James Davis

Reputation: 12295

Try the following: 

$.mockjax({
    url: '/test',
    dataType: 'json',
    responseTime: 2500,
    responseText: ko.unwrap(self.registrationmark)
});

Upvotes: 0

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