lib/jam.js
function continuable(func, context) {
      ensureFunc(func, 'function');

      if (context) { // TODO: Handle falsy things?
        func = bind(func, context);
      }

      steps.push(func);
      return continuable;
    }
function continuable(func, context) {
      ensureFunc(func, 'function');

      if (context) { // TODO: Handle falsy things?
        func = bind(func, context);
      }

      steps.push(func);
      return continuable;
    }
Subsequent invocation of the function returned from the `jam` function simply adds the given function to the chain.