@varasto/query

Collection of useful query and bulk operation utilities for Varasto storages that use simple-json-match schemas for finding entries.

Installation

$ npm install --save @varasto/query

Usage

The package provides following functions.

Searching for single entry

find()

find(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<JsonObject | undefined>

Searches for an entry from given namespace that matches given schema and returns value of first matching result. If no entry in the namespace matches the schema, undefined is returned instead.

findKey()

findKey(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<string | undefined>

Searches for an entry from given namespace that matches given schema and returns key of first matching result. If no entry in the namespace matches the schema, undefined is returned instead.

findEntry()

findEntry(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<[string, JsonObject] | undefined>

Searches for an entry from given namespace that matches given schema and returns both key and value of first matching result. If no entry in the namespace matches the schema, undefined is returned instead.

Searching for multiple entries

findAll()

findAll<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema
): AsyncGenerator<T>

Searches for entries from given namespace that match given schema and returns their values. If no entries match the given schema, empty array is returned instead.

findAllKeys()

findAllKeys(
  storage: Storage,
  namespace: string,
  schema: Schema
): AsyncGenerator<string>

Searches for entries from given namespace that match given schema and returns their keys. If no entries match the given schema, empty array is returned instead.

findAllEntries()

findAllEntries<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema
): AsyncGenerator<[string, T]>

Searches for entries from given namespace that match given schema and returns them in an array. If no entries match the given schema, empty array is returned instead.

Partition utilities

partition()

partition<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<[T[], T[]]>

Splits values of entries from given namespace into two arrays depending on whether they match the given schema. Entries that match the schema will be returned first element of returned array, while the remaining entries will be second.

partitionKeys()

partitionKeys(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<[string[], string[]]>

Splits keys of entries from given namespace into two arrays depending on whether they match the given schema. Entries that match the schema will be returned first element of returned array, while the remaining entries will be second.

partitionEntries()

partitionEntries<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<[[string, T][], [string, T][]]>

Splits entries from given namespace into two arrays depending on whether they match the given schema. Entries that match the schema will be returned first element of returned array, while the remaining entries will be second.

Bulk operations

updateAll()

updateAll<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema,
  value: Partial<T>
): AsyncGenerator<T>

Performs an bulk update where all entries from given namespace that match the given schema are partially updated with given value. Returns updated values or empty array if no entry matched the given schema.

updateAllEntries()

updateAllEntries<T extends JsonObject>(
  storage: Storage,
  namespace: string,
  schema: Schema,
  value: Partial<T>
): AsyncGenerator<[string, T]>

Performs an bulk update where all entries from given namespace that match the given schema are partially updated with given value. Returns updated entries (key and value) or empty array if no entry matched the given schema.

deleteAll()

deleteAll(
  storage: Storage,
  namespace: string,
  schema: Schema
): Promise<number>

Performs an bulk deletion where all entries from the given namespace that match the given schema are deleted. Returns total number of deleted entries or 0 if no entry matched the given schema.