Has

The has(x.f) macro tests whether field f is present on a message x.

// input: user = example.v1.User{name: "Alice"}
has(user.name)
// result: true (bool)

// input: user = example.v1.User{}
has(user.name)
// result: false (bool)

Conditional access

Combine has with the conditional operator for safe field access. This is particularly useful for wrapper types, which evaluate to null when unset.

// input: user = example.v1.User{name: "Alice"}
has(user.nickname) ? user.nickname : user.name
// result: "Alice" (string)

See also

• Protocol Buffers - Protobuf messages
• Well-known types - Wrapper field semantics