52 lines
1.5 KiB
TypeScript
52 lines
1.5 KiB
TypeScript
/**
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* A {@link Migration} contains a target version and a migrate function.
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*
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* The version is used to determine whether the migration has yet to be applied
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* or if it needs to be skipped, see {@link SkipMigrationFn} for details.
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*
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* The migrate function should take the data you pass through {@link migrate}
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* and modify it to your needs.
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*/
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export type Migration<V, A = any, B = any> = {
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version: V;
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migrate: (data: A) => Promise<B>;
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};
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/**
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* A function that determines if a {@link Migration} should be skipped.
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*
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* The first argument will be the version of the current {@link Migration} being
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* tested, while the second argument will be the version passed into
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* {@link migrate}.
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*
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* If left undefined, `a <= b` will be used. This works for {@link Date dates},
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* {@link Number numbers} and {@link String strings}. So if you want to use a
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* different type for versioning you should create your own function.
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*/
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export type SkipMigrationFn<V> = (a: V, b: V) => boolean;
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/**
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* Migrate some data to the specified version.
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*
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* See {@link Migration} and {@link SkipMigrationFn} for details on creating
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* migrations and a custom skip function.
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*/
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export async function migrate<V>(
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data: unknown,
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version: V,
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migrations: Array<Migration<V>>,
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skip: SkipMigrationFn<V> = (a, b) => a <= b,
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): Promise<unknown> {
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let migratedData = data;
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for (const migration of migrations) {
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if (skip(migration.version, version)) {
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continue;
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}
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migratedData = await migration.migrate(migratedData);
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}
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return migratedData;
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}
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