Collection

Overview

The utils.collection.js module provides utility functions for interacting with collections in a KDK-based application.

It leverages Lodash for object manipulation and FeathersJS services to perform database operations efficiently.

Functions

getCollectionService(name, context)

Retrieves a service instance for a specified collection.

• Parameters:
  • name (string): The name of the collection service.
  • context (object): The context in which the service operates.
• Returns: The requested service instance.

listItems(service, fields, filter = {}, limit = 50)

Fetches a list of items from a given service, applying optional filters and field selection.

• Parameters:
  • service (object): The service instance to query.
  • fields (array): The fields to select in the query.
  • filter (object, optional): Additional query filters.
  • limit (number, optional, default=50): The maximum number of items to retrieve.
• Returns: A promise resolving to the list of retrieved items.

getOldestItem(service, field = 'createdAt', filter = {})

Retrieves the oldest item from a service based on a specified field.

• Parameters:
  • service (object): The service instance to query.
  • field (string, optional, default='createdAt'): The field used to determine the oldest item.
  • filter (object, optional): Additional query filters.
• Returns: A promise resolving to the oldest item.

getOldestTime(service, field = 'createdAt', filter = {})

Retrieves the timestamp of the oldest item from a service based on a specified field.

• Parameters:
  • service (object): The service instance to query.
  • field (string, optional, default='createdAt'): The field used to determine the oldest timestamp.
  • filter (object, optional): Additional query filters.
• Returns: A promise resolving to the timestamp of the oldest item.

getLatestItem(service, field = 'createdAt', filter = {})

Retrieves the latest item from a service based on a specified field.

• Parameters:
  • service (object): The service instance to query.
  • field (string, optional, default='createdAt'): The field used to determine the latest item.
  • filter (object, optional): Additional query filters.
• Returns: A promise resolving to the latest item.

getLatestTime(service, field = 'createdAt', filter = {})

Retrieves the timestamp of the latest item from a service based on a specified field.

• Parameters:
  • service (object): The service instance to query.
  • field (string, optional, default='createdAt'): The field used to determine the latest timestamp.
  • filter (object, optional): Additional query filters.
• Returns: A promise resolving to the timestamp of the latest item.

getDistinctValues(service, field, filter = {})

Retrieves a list of distinct values for a specified field in a collection.

• Parameters:
  • service (object): The service instance to query.
  • field (string): The field for which distinct values are required.
  • filter (object, optional): Additional query filters.
• Returns: A promise resolving to an array of unique values.

Example usage

import { getCollectionService, listItems } from './utils.collection.js'

const service = getCollectionService('myCollection', context)
const items = await listItems(service, ['name', 'age'], { active: true }, 100)
console.log('Active items:', items)

searchText(service, text, caseSensitive = false, diacriticSensitive = false)

Searches for a given text in a service using a [$text}(https://www.mongodb.com/docs/manual/reference/operator/query/text/) query.

• Parameters:
  • service (Object) – The service to perform the search on.
  • text (String) – The text to search for.
  • caseSensitive (Boolean, default: false) – Whether the search should be case-sensitive.
  • diacriticSensitive (Boolean, default: false) – Whether the search should be diacritic-sensitive.
• Returns: A promise that resolves to the search results.

Example usage

const results = await searchText(myService, 'example')
console.log(results)

:::
$text performs a text query on the content of the fields indexed with a text index. :::

containsText(service, field, text, caseSensitive = false, diacriticSensitive = false)

Checks if a specific field in the search results contains the exact text.

• Parameters:
  • service (Object) – The service to perform the search on.
  • field (String) – The field to check in the search results.
  • text (String) – The text to match against.
  • caseSensitive (Boolean, default: false) – Whether the comparison should be case-sensitive.
  • diacriticSensitive (Boolean, default: false) – Whether the comparison should consider diacritics.
• Returns: A promise that resolves to true if an exact match is found, otherwise false.