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Where Value Objects represent pieces of immutable data without an identity, entities represent identifiable elements within our systems. Entities generally have a lifecycle. They can be created, oftentimes deleted and are expected to be mutated during their lifespan.

Entities are regarded as equal if their identities are equal. This means that, even if two entities contain different data, as long as their identifying field’s value is the same, they must be regarded as the same entity. In that situation, it’s likely that one of the entities is an updated version of the other.

In this post I’ll discuss how entities can be implemented in Go.

In an ideal world non-technical colleagues would be able to read our code and quickly recognise the concepts, rules and processes that make up the business. We might never reach such an ideal but I’d argue we should strive for it nonetheless. Value Objects offer one way of getting us closer to that ideal situation.

Value Objects are an important building block of Domain Driven Design. They allow for representing certain business concepts using some data and the behaviour related to this data. They do not have an identity, unlike entities, and are considered equal when their data is equal. Lastly, they should be immutable, meaning their data should not change once instantiated.

In this post, I will show you how to create Value Objects in Go that adhere to these properties and how using them can improve your code.