Changed Fields

Each entity tracks which of its fields has changed within the current unit of work/EntityManager:

const a1 = em.load(Author, "1");

// Nothing has changed at first
expect(a1.changes.firstName.hasChanged).toBe(false);

// Now perform some business logic
a1.firstName = "a2";

// And the field shows up has changed
expect(a1.changes.firstName.hasChanged).toBe(true);
expect(a1.changes.firstName.originalValue).toEqual("a1");

The changes API has three methods:

• changes.firstName.hasChanged - is true whenever firstName has been set, either on a new entity or an existing entity
• changes.firstName.hasUpdated - is true only when firstName has been changed on an existing entity
• changes.firstName.originalValue - is the original value, only for an existing entity

Audit Trails

Note the changes API is only for the current in-memory changes being made to an entity, it’s not an audit trail.

That said, Joist entities can be used with 3rd-party audit trail solutions like CyanAudit.