Durandal is not unwrapping observables

Question

I am upgrading my knockout project to durandal and noticed that some standard knockout bindings are not working as expected.

Knockout does not make any difference between this:

<!-- ko text: someObservable" --><!-- /ko -->

and this:

<!-- ko text: someObservable()" --><!-- /ko -->

Durandal's composition engine does not seem to handle the first case (without parantheses) correctly. I end up with string representation of dependentObservable function instead of it's value:

function dependentObservable() {          if (arguments.length > 0) {              if (typeof writeFunction === "function") {                  // Writing a value                  writeFunction.apply(evaluatorFunctionTarget, arguments);              } else {                  throw new Error("Cannot write a value to a ko.computed unless you specify a 'write' option. If you wish to read the current value, don't pass any parameters.");              }              return this; // Permits chained assignments          } else {              // Reading the value              if (!_hasBeenEvaluated)                  evaluateImmediate();              ko.dependencyDetection.registerDependency(dependentObservable);              return _latestValue;          }      }

Does durandal require parantheses at the end of binding string or is it configurable somehow?

Answer 1

The problem was that I included knockout library twice: it was loaded both synchronously and via requirejs. It turns out requirejs will still load script, even if it is already loaded synchronously.

Adding this to main.js solves the problem:

define('knockout', [], function() {
    return ko;
});