Gabby-query-protocol-projection NPM

gabby-query-protocol-projection

Utility to assist with field selection routines. AKA: Column selection utility.

Installation

Using npm:

$ npm install gabby-query-protocol-projection

Documentation

This Repo's docs

Project's docs

./examples/* contains executable snippets found in documentation.

Description

This is a sub-project the Gabby Query Protocol. The purpose of this project is to provide utilities for column selection (a projection).

projection - a field, or column, or similar, or a collection thereof. Possible uses of a projection:

SELECT [projection]
ORDER BY [projection]
record definition
non-SQL column definition

Main classes/types

A projection item:

type TProjectionItemProperties = {
  subjectId: string;
  sortOrder: number; // between [-1,1]
  columnOrder: number; // any number ok. This is not position
  label: string;
};

A projection:

type TProjection = TProjectionItemProperties[];

A Projection Editor:

export interface IProjectionEditor {
  addSubject(projection: TProjectionItemProperties): string;

  getProjectableSubjectsDictionary(): IProjectableSubjectDictionary;

  getSubProjectionBySubjectId(subjectId: string): TProjectionDictionary;

  getKeys(): string[];

  getProjectionOrderByColumPosition(): TProjectionDictionary;

  getProjectionSubject(key: string): TProjectionItemProperties;

  removeProjectionSubject(key: string): void;

  updateSubject(key: string, props: TProjectionPropertiesUpdatable): void;

  toJson(): TProjectionItemProperties[];
}

Projectable Subject (field properties to be used to create projectionItem)

export type TProjectableSubjectProperties = {
  isSortable: boolean; // this would likely used in things like ORDER BY
  datatype: TSupportedDatatype;
  defaultLabel: string;
};

Example

Simple usage:

import { ProjectionEditorFactory } from "gabby-query-protocol-projection";
import { EXAMPLE_JSON_BLUE_SKIES } from "gabby-query-protocol-projection";

const { projectionJson: projectionItemsJson } = EXAMPLE_JSON_BLUE_SKIES;
const { projectableSubjectDictionaryJson } = EXAMPLE_JSON_BLUE_SKIES;

export const exampleProjectionEditor = ProjectionEditorFactory.fromJson({
  projectableSubjectDictionaryJson,
  projectionItemsJson, // optional, if undefined a new default projection created
});

const projectionItemId = exampleProjectionEditor.addSubject({
  label: "My New Projection Item",
  subjectId: "lastname",
  columnOrder: 1000,
  sortOrder: -1,
});

exampleProjectionEditor.updateSubject(projectionItemId, { columnOrder: 10 });

console.log(exampleProjectionEditor.getProjectionOrderByColumPosition());