pg-promise-demo/JavaScript/db/repos/users.js

Advanced demo of using pg-promise.

const {users: sql} = require('../sql');

const cs = {}; // Reusable ColumnSet objects.

/*
 This repository mixes hard-coded and dynamic SQL, primarily to show a diverse example of using both.
 */

class UsersRepository {
    constructor(db, pgp) {
        this.db = db;
        this.pgp = pgp;

        // set-up all ColumnSet objects, if needed:
        createColumnsets(pgp);
    }

    // Creates the table;
    create() {
        return this.db.none(sql.create);
    }

    // Initializes the table with some user records, and return their id-s;
    init() {
        return this.db.map(sql.init, [], row => row.id);
    }

    // Drops the table;
    drop() {
        return this.db.none(sql.drop);
    }

    // Removes all records from the table;
    empty() {
        return this.db.none(sql.empty);
    }

    // Adds a new user, and returns the new object;
    add(name) {
        return this.db.one(sql.add, name);
    }

    // Tries to delete a user by id, and returns the number of records deleted;
    remove(id) {
        return this.db.result('DELETE FROM users WHERE id = $1', +id, r => r.rowCount);
    }

    // Tries to find a user from id;
    findById(id) {
        return this.db.oneOrNone('SELECT * FROM users WHERE id = $1', +id);
    }

    // Tries to find a user from name;
    findByName(name) {
        return this.db.oneOrNone('SELECT * FROM users WHERE name = $1', name);
    }

    // Returns all user records;
    all() {
        return this.db.any('SELECT * FROM users');
    }

    // Returns the total number of users;
    total() {
        return this.db.one('SELECT count(*) FROM users', [], a => +a.count);
    }
}

//////////////////////////////////////////////////////////
// Example of statically initializing ColumnSet objects:

function createColumnsets(pgp) {
    // create all ColumnSet objects only once:
    if (!cs.insert) {
        // Type TableName is useful when schema isn't default "public" ,
        // otherwise you can just pass in a string for the table name.
        const table = new pgp.helpers.TableName({table: 'users', schema: 'public'});

        cs.insert = new pgp.helpers.ColumnSet(['name'], {table});
        cs.update = cs.insert.extend(['?id']);
    }
    return cs;
}

module.exports = UsersRepository;