@typespec/versioning

TypeSpec library for declaring and emitting versioned APIs

Install

npm install @typespec/versioning

Usage

Consuming versioning library from an emitter

Get the service representation at a given version

Versioning library works with projection to project the service at a given version.

// Get a list of all the different version of the service and the projections
const projections = buildVersionProjections(program, serviceNamespace);

for (const projection of projections) {
  const projectedProgram = projectProgram(program, projection.projections);
  // projectedProgram now contains the representation of the service at the given version.
}

Get list of versions and version dependency across namespaces

Versioning library works with projection to project the service at a given version.

const versions = resolveVersions(program, serviceNamespace);
// versions now contain a list of all the version of the service namespace and what version should all the other dependencies namespace use.

Consume versioning manually

If the emitter needs to have the whole picture of the service evolution across the version then using the decorator accessor will provide the metadata for each type:

• getAddedOn
• getRemovedOn
• getRenamedFromVersion
• getMadeOptionalOn

Decorators

TypeSpec.Versioning

• @added
• @madeOptional
• @removed
• @renamedFrom
• @returnTypeChangedFrom
• @typeChangedFrom
• @useDependency
• @versioned

@added

Identifies when the target was added.

@TypeSpec.Versioning.added(version: EnumMember)

Target

Model | ModelProperty | Operation | Enum | EnumMember | Union | UnionVariant | Scalar | Interface

Parameters

Name	Type	Description
version	EnumMember	The version that the target was added in.

Examples

@added(Versions.v2)
op addedInV2(): void;

@added(Versions.v2)
model AlsoAddedInV2 {}

model Foo {
  name: string;

  @added(Versions.v3)
  addedInV3: string;
}

@madeOptional

Identifies when a target was made optional.

@TypeSpec.Versioning.madeOptional(version: EnumMember)

Target

ModelProperty

Parameters

Name	Type	Description
version	EnumMember	The version that the target was made optional in.

Examples

model Foo {
  name: string;

  @madeOptional(Versions.v2)
  nickname: string;
}

@removed

Identifies when the target was removed.

@TypeSpec.Versioning.removed(version: EnumMember)

Target

Model | ModelProperty | Operation | Enum | EnumMember | Union | UnionVariant | Scalar | Interface

Parameters

Name	Type	Description
version	EnumMember	The version that the target was removed in.

Examples

@removed(Versions.v2)
op removedInV2(): void;

@removed(Versions.v2)
model AlsoRemovedInV2 {}

model Foo {
  name: string;

  @removed(Versions.v3)
  removedInV3: string;
}

@renamedFrom

Identifies when the target has been renamed.

@TypeSpec.Versioning.renamedFrom(version: EnumMember, oldName: valueof string)

Target

Model | ModelProperty | Operation | Enum | EnumMember | Union | UnionVariant | Scalar | Interface

Parameters

Name	Type	Description
version	EnumMember	The version that the target was renamed in.
oldName	valueof string	The previous name of the target.

Examples

@renamedFrom(Versions.v2, "oldName")
op newName(): void;

@returnTypeChangedFrom

Identifies when the target type changed.

@TypeSpec.Versioning.returnTypeChangedFrom(version: EnumMember, oldType: unknown)

Target

Operation

Parameters

Name	Type	Description
version	EnumMember	The version that the target type changed in.
oldType	unknown	The previous type of the target.

@typeChangedFrom

Identifies when the target type changed.

@TypeSpec.Versioning.typeChangedFrom(version: EnumMember, oldType: unknown)

Target

ModelProperty

Parameters

Name	Type	Description
version	EnumMember	The version that the target type changed in.
oldType	unknown	The previous type of the target.

@useDependency

Identifies that a namespace or a given versioning enum member relies upon a versioned package.

@TypeSpec.Versioning.useDependency(...versionRecords: EnumMember[])

Target

EnumMember | Namespace

Parameters

Name	Type	Description
versionRecords	EnumMember[]	The dependent library version(s) for the target namespace or version.

Examples

Select a single version of MyLib to use

@useDependency(MyLib.Versions.v1_1)
namespace NonVersionedService;

Select which version of the library match to which version of the service.

@versioned(Versions)
namespace MyService1;
enum Version {
  @useDependency(MyLib.Versions.v1_1) // V1 use lib v1_1
  v1,
  @useDependency(MyLib.Versions.v1_1) // V2 use lib v1_1
  v2,
  @useDependency(MyLib.Versions.v2) // V3 use lib v2
  v3,
}

@versioned

Identifies that the decorated namespace is versioned by the provided enum.

@TypeSpec.Versioning.versioned(versions: Enum)

Target

Namespace

Parameters

Name	Type	Description
versions	Enum	The enum that describes the supported versions.

Examples

@versioned(Versions)
namespace MyService;
enum Versions {
  v1,
  v2,
  v3,
}