Javascript: Update the value of an Object fields

Question

I have the following code:

var view = function () {

var formset_prefix = '', form_id = '';

var DOMStrings = {
    formset_total: 'TOTAL_FORMS',
    formset: '*[id$=-TOTAL_FORMS]',
    field: '*[id^=id_' + formset_prefix + '-]',
    field_idx = '*[id^=id_' + formset_prefix + form_id +'-]'

};

return {
....................
get_form_fields: function (prefix, id) {
            formset_prefix = prefix;
            form_id = id;
            console.log(formset_prefix);
            console.log(DOMStrings.field);
            return document.querySelectorAll(DOMStrings.field);
        }
..... }();

I don't know at the beginning what is the formset_prefix and formset_id, but I get them later using multiple function calls, so I initialize them at the beginning with empty.

Hoe can I force the update of the DOMStrings object attributes field and formset later when I update the formset_prefix and formset_id values ?

Answer 1

One option is to make DOMStrings a function and compute the object on the fly:

var formset_prefix = '', form_id = '';

var DOMStrings = function() {
    return {
       formset_total: 'TOTAL_FORMS',
       formset: '*[id$=-TOTAL_FORMS]',
       field: '*[id^=id_' + formset_prefix + '-]'
    }
}

return {
....................
get_form_fields: function (prefix, id) {
            formset_prefix = prefix;
            form_id = id;
            return document.querySelectorAll(DOMStrings().field);
        }
..... }();

Better yet, decouple it from the context, and pass necessary parameters as arguments:

var DOMStrings = function(prefix, id) {
    return {
       formset_total: 'TOTAL_FORMS',
       formset: '*[id$=-TOTAL_FORMS]',
       field: '*[id^=id_' + prefix + '-]'
    }
}

return {
....................
get_form_fields: function (prefix, id) {
            var strings = DOMStrings(prefix, id);
            return document.querySelectorAll(strings.field);
        }
..... }();