"wrap" function makes computed writable

[lisandropuzzolo]

On function withProxyDependentObservable, the wrap function makes all computed writable.

Solution:

function withProxyDependentObservable(dependentObservables, callback) {
var localDO = ko.dependentObservable;
ko.dependentObservable = function (read, owner, options) {
options = options || {};

        if (read && typeof read == "object") { // mirrors condition in knockout implementation of DO's
            options = read;
        }

        var realDeferEvaluation = options.deferEvaluation;

        var isRemoved = false;

        // We wrap the original dependent observable so that we can remove it from the 'dependentObservables' list we need to evaluate after mapping has
        // completed if the user already evaluated the DO themselves in the meantime.
        var wrap = function (DO) {
            var wrapped = realKoDependentObservable({
                read: function () {
                    if (!isRemoved) {
                        ko.utils.arrayRemoveItem(dependentObservables, DO);
                        isRemoved = true;
                    }
                    return DO.apply(DO, arguments);
                },
                write: DO.hasWriteFunction && function (val) { //  ***** HERE IS THE FIX *****
                    return DO(val);
                },
                deferEvaluation: true
            });
            if(DEBUG) wrapped._wrapper = true;
            return wrapped;
        };

        options.deferEvaluation = true; // will either set for just options, or both read/options.
        var realDependentObservable = new realKoDependentObservable(read, owner, options);

        if (!realDeferEvaluation) {
            realDependentObservable = wrap(realDependentObservable);
            dependentObservables.push(realDependentObservable);
        }

        return realDependentObservable;
    }
    ko.dependentObservable.fn = realKoDependentObservable.fn;
    ko.computed = ko.dependentObservable;
    var result = callback();
    ko.dependentObservable = localDO;
    ko.computed = ko.dependentObservable;
    return result;
}

[sagacity]

Thanks for letting me know. This will be fixed in the next release.

[wjbryant]

It looks like hasWriteFunction is considered part of the private API since it's mangled/obfuscated in the minified build. Replacing DO.hasWriteFunction with ko.isWriteableObservable(DO) should work in both the debug and minified builds.

[sagacity]

Good catch, I'll fix that.