How to Check for Entity Changes

  • The Session tracks all changes made to all entities that it has either loaded, stored, or queried for,
    and persists to the server only what is needed when saveChanges() is called.

  • This article describes how to check for changes made in a specific entity within a session.
    To check for changes on all tracked entities, see Check for session changes.

  • In this page:

Check for entity changes

  • The session's advanced property hasChanged indicates whether the specified entity was added, modified, or deleted within the session.

  • Note: The hasChanged property is cleared after calling saveChanges().

// Store a new entity within the session
// =====================================

let employee = new Employee();
employee.firstName = "John";
employee.lastName = "Doe";
await, "employees/1-A");

// 'hasChanged' will be TRUE 

// 'hasChanged' will reset to FALSE after saving changes 
await session.saveChanges();

// Load & modify entity within the session
// =======================================

employee = await session.load("employees/1-A");
assert.ok(!session.advanced.hasChanged(employee));   // FALSE

employee.lastName = "Brown";
assert.ok(session.advanced.hasChanged(employee));    // TRUE

await session.saveChanges();
assert.ok(!session.advanced.hasChanged(employee));   // FALSE