@t-box/specification

The T-box specification module handles generating queries based on conditional expressions in code. This tries to mimic linq where clauses and expressions from C#.

Features

• Simplify database queries for mongoose
• Generates smart queries and tries to consolidate where possible
• No dependencies

Installation

NPM

    npm install @t-box/specification

Yarn

    yarn install @t-box/specification

Usage

The basic usage of this is to generate queries for specific ORM's in nodeJs

    // Adaptor is needed to determine how to build out the query.  In this case it is the mongoose adaptor.
    import '@t-box/specification/adaptors/mongoose/adaptor';
    import { Specification } from '@t-box/specification';

    // Create a query where isDeleted is equal to false.
    let boolSpec = new Specification<IPerson>(x => x.isDeleted === false);
    boolSpec.query(); // This will generate the mongoose query ready to be sent off.

More complex queries can be created, and even varables can be sent into be processed as well.

    // Adaptor is needed to determine how to build out the query.  In this case it is the mongoose adaptor.
    import '@t-box/specification/adaptors/mongoose/adaptor';
    import { Specification } from '@t-box/specification';

    // Create a query where isDeleted is equal to false.
    let firstName = 'John';
    let startAge = 10;
    let endAge = 20;
    let andOr = new Specification<IPerson>(x => x.isDeleted && x.firstName === firstName && (x.age > startAge || x.age < endAge), { firstName, startAge, endAge });
    boolSpec.query(); // This will generate the mongoose query ready to be sent off.

The second argument to the specification is used to deal with variables passed into the arrow function.

Future

This module needs a lot of work before I would suggest using it in a live project. The following are the areas that need to be worked on

• Speed
• Allow Functions in the query
• Typescript compiler plugin to add in the variables on build
• Add in extra adaptors, working on sequelize now

License

@t-box/specification is licensed under the MIT license.