@statesync/persistence

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@statesync/persistence / createMigrationBuilder

Function: createMigrationBuilder()

function createMigrationBuilder<TFinal>(): MigrationBuilder<TFinal>;

Defined in: persistence/src/migration.ts:139

Creates a fluent builder for constructing MigrationHandler instances with full type safety across migration steps.

The builder pattern ensures each migration step is explicitly typed, making it harder to introduce schema mismatches.

Type Parameters

Type Parameter	Description
TFinal	The shape of the application state in the final (current) schema version.

Returns

MigrationBuilder<TFinal>

A new MigrationBuilder instance with no migrations registered.

Example

interface AppStateV1 { count: number }
interface AppStateV2 { count: number; name: string }
interface AppStateV3 { count: number; name: string; enabled: boolean }

const migration = createMigrationBuilder<AppStateV3>()
  .addMigration<AppStateV1, AppStateV2>(1, (v1) => ({ ...v1, name: 'default' }))
  .addMigration<AppStateV2, AppStateV3>(2, (v2) => ({ ...v2, enabled: true }))
  .build(3);