Session: How to Check if There are Any Changes on a Session

Property indicates if the session contains any changes. If there are any new, changed or deleted entities.

session.advanced.hasChanges();

Example

{
    const session = store.openSession();

    assert.ok(!session.advanced.hasChanges());

    const employee = new Employee();
    employee.firstName = "John";
    employee.lastName = "Doe";

    await session.store(employee);

    assert.ok(session.advanced.hasChanges());
}

Method returns all changes for each entity stored within the session. Including name of the field/property that changed, its old and new value, and change type.

session.advanced.whatChanged();

Example I

{
    const session = store.openSession();

    const employee = new Employee();
    employee.firstName = "John";
    employee.lastName = "Doe";

    await session.store(employee);

    const changes = session.advanced.whatChanged();
    const employeeChanges = changes["employees/1-A"];
    const change =
        employeeChanges[0].change; // "DocumentAdded"

}

Example II

const session = store.openSession();
const employee = await session.load("employees/1-A"); // 'Joe Doe'
employee.firstName = "John";
employee.lastName = "Shmoe";

const changes = session.advanced.whatChanged();
const employeeChanges = changes["employees/1-A"];
const change1 = employeeChanges[0]; // "FieldChanged"
const change2 = employeeChanges[1]; // "FieldChanged"