How can we use hashtable caching? What is the advantage of using the same?

Hai,i am writing code for to delete and release the binding for office app but it shows that error can u send me how to solve that error
pub.deleteDataAndReleaseMatrixBinding = function deleteData(bindingId, callBack) {


Office.context.document.bindings.getByIdAsync(bindingId, function (asyncResult) {

What is lapping length and what is development length?