pg-ninja

pg-ninja

---

a lightweight asynchronous library for executing PostgreSQL queries and transactions

installation

---

$ npm i pg-ninja

usage

---

library have only 3 functions, for queries, transactions and multi-queries that will help you with testing or filling your database and queries base.

Import

import database from 'pg-ninja'

const connection = new database({
	user: 'admin',
	password: 'admin',
	host: 'localhost',
	database: 'project',
});

Constructor

new database(connection: JSON): object

JSON connection object for 'pg'

---

Queries

sending PostgreSQL query and returns result of it

syntax:

connection.query(query: string, ...parameters: Array<any>): Promise

promise returns only resolve value, no reject.

result syntax:

[status: boolean, result: object]: Array

status: true - success query, false - any error on query (syntax, permissions, wrong names, etc.)

result: on true - query body from 'pg', on false - Error body from 'pg'

regular promise handler:

connection.query('SELECT 1 AS test;').then(res => {
	console.log(res[0]); // true
	console.log(res[1]?.rows?.[0]); // { test: 1 }
});

async/await promise handler:

async function test() {
	let responce = await connection.query('SELECT 1 AS test;');
    
    console.log(responce[0]); // true
    console.log(responce[1]?.rows?.[0]); // { test: 1 }
    
    return responce;
}

test();

---

Transactions

sendind PostgreSQL transaction and returns result of it; on success commit transaction, on any error - rollback.

syntax

connection.transaction(queries: Array<Array>): Promise

queries - Array of <queries> for connection.query() - [query, ...parametrs]

promise returns only resolve value, no reject

result syntax:

[status: boolean, result: object, ...index: integer]

status: true - success query, false - any error on query

result: on true - last query body from 'pg', on false - first Error body from 'pg'

index: on Query error (non fatal error) return index of problem query with rollback transaction

regular promise handler:

connection.transaction([
	[ 'SELECT 1 AS test;' ],
	[ 'SELECT $1 AS test;', [1] ],
]).then(res => {
	console.log(res[1]?.rows?.[0]); // { test: '1' }
});

async/await promise handler:

async function test() {
    let responce = await connection.transaction([
		[ 'SELECT 1 AS test;' ],
		[ 'SELECT $1 AS test;', [1] ],
	]);

	console.log(responce[1]?.rows?.[0]); // { test: '1' }
    
    return responce;
}

test();

---

Multi queries

PostgreSQL shell for testing queries base or database security and filling tables

syntax

connection.multiquery(queries: Array<Array>, save_success=false: boolean): Promise

queries - Array of <queries> for connection.query() - [query, ...parametrs]

save_success - true - success results of queries will be saved in responce.success_query_list, false (default value) - responce.success_query_list will be empty

promise returns only resolve value, no reject

result syntax:

responce: object

responce methods:

completed: integer - number of success completed queries
completed_of: integer - number of all queries
success_query_list: object JSON - array with results of success queries, where result index = query index in [...`<queries>`]
failed_query_list: object JSON - array of failed queries (: string), where query index = query index in [...`<queries>`]
error_list: object JSON - array with results of failed queries, where result index = query index in [...`<queries>`]
fatal_error: object - `undefined` in no fatal error or Error Object in case of fatal error
operation_time: integer - time in ms (divide by 1000 for seconds) for operate all queries
success: boolean - true on no Fatal Error (responce.fatal_error), false on Fatal Error (responce.fatal_error)

regular promise handler:

connection.multiquery([
	[ 'SELECT * FROM users;' ], // users exist
	[ 'SELECT * FROM users WHERE id = $1', [1] ], // users exist but no users.id=1 -> 0 rows
	[ 'SELECT * FROM potato;' ], // no potato :( 
]).then(res => {
	console.log(`Completed ${res.completed} / ${res.completed_of} quries`); // Completed 2 / 3 queries
	for (let x in res.failed_query_list) {
		console.log(`Error in query №${x} - ${res.failed_query_list[x]}`); // Error in query №2 - SELECT * FROM potato;
	};
});

async/await promise handler:

async function test() {
	let responce = await connection.multiquery([
        [ 'SELECT * FROM users;' ], // users exist
        [ 'SELECT * FROM users WHERE id = $1', [1] ], // users exist but no users.id=1 -> 0 rows
        [ 'SELECT * FROM potato;' ], // no potato :( 
    ]);

	console.log(`Completed ${responce.completed} / ${responce.completed_of} quries`); // Completed 2 / 3 queries
	for (let x in responce.failed_query_list) {
		console.log(`Error in query №${x} - ${responce.failed_query_list[x]}`); // Error in query №2 - SELECT * FROM potato;
    }
}

test();