knexjs extra helpers

⚠️ Work in progress ⚠️

This package provides several helpers to be used with knex.

• installation
• usage
  • querying
    • pagination
  • managing relations
    • one-to-one
    • one-to-many
  • prefix

Installation

yarn add @ekino/knex-extra

Usage

Querying

Pagination

import { applyLimitAndOffset } from '@ekino/knex-extra'

Managing relations

Some drivers for knex do not support nesting results children, for example when using joins, this package provide a handy helper nest which ease the process of extracting relations.

When implemented, it will generate 2 functions, selection() which can be used to automatically generate the columns to select, and rollup() which can be used to transform rows to nested objects.

one-to-one relations

Let say we have posts and users, each post being authored by an author (user). In order to define the relation from posts to author, you'll have to implement something like that:

import { nest } from '@ekino/knex-extra'

const postsRelations = nest('posts', ['id', 'title']).one('author', ['id', 'username'])

const findPostsWithAuthor = async () => {
    const rows = await knex
        .select(postsRelations.selection())
        // must match the table name defined when calling `.nest()`
        .from('posts')
        // note the usage of an alias (`author`), it's required
        // as it's the key we used when defining `.one()` relationship
        .leftJoin('users as author', 'author.id', 'posts.author_id')

    // for now, rows are flat objects with column names prefixed with table name:
    // [
    //   {
    //     posts__id: 1,
    //     posts__title: 'An interesting post',
    //     author__id: 12,
    //     author__username: 'plouc'
    //   },
    //   ...
    // ]
    // after applying `.rollup()`, table name will be removed from column names
    // and we'll have an `author` property on each one:
    // [
    //   {
    //     id: 1,
    //     title: 'An interesting post',
    //     author: {
    //       id: 12,
    //       username: 'plouc'
    //     }
    //   },
    //   ...
    // ]
    return postsRelations.rollup(rows)
}

one-to-many relations

import { nest } from '@ekino/knex-extra'

Prefix