deno.land / x / replicache@v10.0.0-beta.0 / scan-iterator.ts
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type ScanKey = string | IndexKey;
type ToValue<Options extends ScanOptions, V> = ( entry: EntryForOptions<Options>,) => V;
type ShouldDeepClone = {shouldDeepClone: boolean};
/** * This class is used for the results of [[ReadTransaction.scan|scan]]. It * implements `AsyncIterable<JSONValue>` which allows you to use it in a `for * await` loop. There are also methods to iterate over the [[keys]], * [[entries]] or [[values]]. */export class ScanResultImpl< Options extends ScanOptions, V extends ReadonlyJSONValue,> implements ScanResult<KeyTypeForScanOptions<Options>, V>{ private readonly _iter: AsyncIterable<EntryForOptions<Options>>; private readonly _options: Options; private readonly _dbDelegateOptions: Closed & ShouldDeepClone; private readonly _onLimitKey: (inclusiveLimitKey: string) => void;
constructor( iter: AsyncIterable<EntryForOptions<Options>>, options: Options, dbDelegateOptions: Closed & ShouldDeepClone, onLimitKey: (inclusiveLimitKey: string) => void, ) { this._iter = iter; this._options = options; this._dbDelegateOptions = dbDelegateOptions; this._onLimitKey = onLimitKey; }
/** The default AsyncIterable. This is the same as [[values]]. */ [Symbol.asyncIterator](): AsyncIterableIteratorToArrayWrapper<V> { return this.values(); }
/** Async iterator over the values of the [[ReadTransaction.scan|scan]] call. */ values(): AsyncIterableIteratorToArrayWrapper<V> { const clone = this._dbDelegateOptions.shouldDeepClone ? deepClone : (x: ReadonlyJSONValue) => x; return new AsyncIterableIteratorToArrayWrapper( this._newIterator(e => clone(e[1])) as AsyncIterableIterator<V>, ); }
/** * Async iterator over the keys of the [[ReadTransaction.scan|scan]] * call. If the [[ReadTransaction.scan|scan]] is over an index the key * is a tuple of `[secondaryKey: string, primaryKey]` */ keys(): AsyncIterableIteratorToArrayWrapper<KeyTypeForScanOptions<Options>> { type K = KeyTypeForScanOptions<Options>; const toValue = (e: EntryForOptions<Options>) => e[0]; return new AsyncIterableIteratorToArrayWrapper( this._newIterator(toValue as ToValue<Options, K>), ); }
/** * Async iterator over the entries of the [[ReadTransaction.scan|scan]] * call. An entry is a tuple of key values. If the * [[ReadTransaction.scan|scan]] is over an index the key is a tuple of * `[secondaryKey: string, primaryKey]` */ entries(): AsyncIterableIteratorToArrayWrapper< readonly [KeyTypeForScanOptions<Options>, V] > { type K = KeyTypeForScanOptions<Options>; const clone = this._dbDelegateOptions.shouldDeepClone ? deepClone : (x: ReadonlyJSONValue) => x; const toValue = (e: EntryForOptions<Options>) => clone(e); return new AsyncIterableIteratorToArrayWrapper( this._newIterator(toValue as ToValue<Options, readonly [K, V]>), ); }
/** Returns all the values as an array. Same as `values().toArray()` */ toArray(): Promise<V[]> { return this.values().toArray(); }
private _newIterator<T>( toValue: ToValue<Options, T>, ): AsyncIterableIterator<T> { return scanIterator( toValue, this._iter, this._options, this._dbDelegateOptions, this._onLimitKey, ); }}
export interface ScanResult<K extends ScanKey, V extends ReadonlyJSONValue> extends AsyncIterable<V> { /** The default AsyncIterable. This is the same as [[values]]. */ [Symbol.asyncIterator](): AsyncIterableIteratorToArrayWrapper<V>;
/** Async iterator over the values of the [[ReadTransaction.scan|scan]] call. */ values(): AsyncIterableIteratorToArrayWrapper<V>;
/** * Async iterator over the keys of the [[ReadTransaction.scan|scan]] * call. If the [[ReadTransaction.scan|scan]] is over an index the key * is a tuple of `[secondaryKey: string, primaryKey]` */ keys(): AsyncIterableIteratorToArrayWrapper<K>;
/** * Async iterator over the entries of the [[ReadTransaction.scan|scan]] * call. An entry is a tuple of key values. If the * [[ReadTransaction.scan|scan]] is over an index the key is a tuple of * `[secondaryKey: string, primaryKey]` */ entries(): AsyncIterableIteratorToArrayWrapper<readonly [K, V]>;
/** Returns all the values as an array. Same as `values().toArray()` */ toArray(): Promise<V[]>;}
/** * A class that wraps an async iterable iterator to add a [[toArray]] method. * * Usage: * * ```ts * const keys: string[] = await rep.scan().keys().toArray(); * ``` */export class AsyncIterableIteratorToArrayWrapper<V> implements AsyncIterableIterator<V>{ private readonly _it: AsyncIterableIterator<V>;
// eslint-disable-next-line @typescript-eslint/no-explicit-any readonly next: (v?: any) => Promise<IteratorResult<V>>; // eslint-disable-next-line @typescript-eslint/no-explicit-any readonly return?: (value?: any) => Promise<IteratorResult<V>>; // eslint-disable-next-line @typescript-eslint/no-explicit-any readonly throw?: (e?: any) => Promise<IteratorResult<V>>;
constructor(it: AsyncIterableIterator<V>) { this._it = it;
// eslint-disable-next-line @typescript-eslint/no-explicit-any this.next = (v: any) => it.next(v); // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-non-null-assertion this.return = it.return ? (v: any) => it.return!(v) : undefined; // eslint-disable-next-line @typescript-eslint/no-explicit-any, @typescript-eslint/no-non-null-assertion this.throw = it.throw ? (v: any) => it.throw!(v) : undefined; }
toArray(): Promise<V[]> { return asyncIterableToArray(this._it); }
[Symbol.asyncIterator](): AsyncIterableIterator<V> { return this._it[Symbol.asyncIterator](); }}
async function* scanIterator<Options extends ScanOptions, V>( toValue: ToValue<Options, V>, iter: AsyncIterable<EntryForOptions<Options>>, options: Options, closed: Closed, onLimitKey: (inclusiveLimitKey: string) => void,): AsyncIterableIterator<V> { throwIfClosed(closed);
let {limit = Infinity} = options; const {prefix = ''} = options; let exclusive = options.start?.exclusive;
const isIndexScan = isScanIndexOptions(options);
// iter has already been moved to the first entry for await (const entry of iter) { const key = entry[0]; const keyToMatch: string = isIndexScan ? key[0] : (key as string); if (!keyToMatch.startsWith(prefix)) { return; }
if (exclusive) { exclusive = true; if (isIndexScan) { // eslint-disable-next-line @typescript-eslint/no-non-null-assertion if (shouldSkipIndexScan(key as IndexKey, options.start!.key)) { continue; } } else { // eslint-disable-next-line @typescript-eslint/no-non-null-assertion if (shouldSkipNonIndexScan(key as string, options.start!.key)) { continue; } } }
yield toValue(entry);
if (--limit === 0 && !isIndexScan) { onLimitKey(key as string); return; } }}
function shouldSkipIndexScan( key: IndexKey, startKey: ScanOptionIndexedStartKey,): boolean { const [secondaryStartKey, primaryStartKey] = normalizeScanOptionIndexedStartKey(startKey); const [secondaryKey, primaryKey] = normalizeScanOptionIndexedStartKey(key); if (secondaryKey !== secondaryStartKey) { return false; } if (primaryStartKey === undefined) { return true; } return primaryKey === primaryStartKey;}
function shouldSkipNonIndexScan(key: string, startKey: string): boolean { return key === startKey;}
/** * This is called when doing a [[ReadTransaction.scan|scan]] without an * `indexName`. * * @param fromKey The `fromKey` is computed by `scan` and is the key of the * first entry to return in the iterator. It is based on `prefix` and * `start.key` of the [[ScanNoIndexOptions]]. */export type GetScanIterator = ( fromKey: string,) => AsyncIterable<ReadonlyEntry<ReadonlyJSONValue>>;
/** * This is called when doing a [[ReadTransaction.scan|scan]] with an * `indexName`. * * @param indexName The name of the index we are scanning over. * @param fromSecondaryKey The `fromSecondaryKey` is computed by `scan` and is * the secondary key of the first entry to return in the iterator. It is based * on `prefix` and `start.key` of the [[ScanIndexOptions]]. * @param fromPrimaryKey The `fromPrimaryKey` is computed by `scan` and is the * primary key of the first entry to return in the iterator. It is based on * `prefix` and `start.key` of the [[ScanIndexOptions]]. */export type GetIndexScanIterator = ( indexName: string, fromSecondaryKey: string, fromPrimaryKey: string | undefined,) => AsyncIterable<readonly [key: IndexKey, value: ReadonlyJSONValue]>;
/** * A helper function that makes it easier to implement [[ReadTransaction.scan]] * with a custom backend */export function makeScanResult<Options extends ScanOptions>( options: Options, getScanIterator: Options extends ScanIndexOptions ? GetIndexScanIterator : GetScanIterator,): ScanResult<KeyTypeForScanOptions<Options>, ReadonlyJSONValue> { type AsyncIter = AsyncIterable<EntryForOptions<Options>>;
if (isScanIndexOptions(options)) { const [fromSecondaryKey, fromPrimaryKey] = fromKeyForIndexScan(options); const iter = (getScanIterator as GetIndexScanIterator)( options.indexName, fromSecondaryKey, fromPrimaryKey, ) as AsyncIter; return new ScanResultImpl( iter, options, {closed: false, shouldDeepClone: false}, _ => { // noop }, ); } const fromKey = fromKeyForNonIndexScan(options); const iter = (getScanIterator as GetScanIterator)(fromKey) as AsyncIter;
return new ScanResultImpl( iter, options, {closed: false, shouldDeepClone: false}, _ => { // noop }, );}export function fromKeyForIndexScan( options: ScanIndexOptions,): readonly [secondary: string, primary?: string] { const {prefix, start} = options; const prefixNormalized: [secondary: string, primary?: string] = [ prefix ?? '', undefined, ];
if (!start) { return prefixNormalized; }
const startKeyNormalized = normalizeScanOptionIndexedStartKey(start.key); if (startKeyNormalized[0] > prefixNormalized[0]) { return startKeyNormalized; } if ( startKeyNormalized[0] === prefixNormalized[0] && startKeyNormalized[1] !== undefined ) { return startKeyNormalized; }
return prefixNormalized;}
export function fromKeyForIndexScanInternal(options: ScanIndexOptions): string { const {prefix, start} = options; let prefix2 = ''; if (prefix !== undefined) { prefix2 = encodeIndexScanKey(prefix, undefined); } if (!start) { return prefix2; }
const {key} = start; const [secondary, primary] = normalizeScanOptionIndexedStartKey(key); const startKey = encodeIndexScanKey(secondary, primary);
if (startKey > prefix2) { return startKey; }
return prefix2;}
replicache
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