What is lapping length and what is development length?

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) {

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