Nathan Hoad


Klein: Combining knex with Immutable.js

I'm a big fan of knex as a database wrapper and am a heavy user of Immutable.js on the client side for data handling in React/Redux.

Previously, I had used Bookshelf as an ORM because it provided a simple interface to manage basic CRUD actions on models and their relationships. While I do like Bookshelf, there were a few things that didn't sit right with me. I like immutable data structures and Bookshelf doesn't use them. I also think the relationship management is more complicated than it needed to be for what I was using. With those two things in mind (plus a bunch of smaller gripes) I set out to make a simple ORM that would combine knex with Immutable.js for immutable data.

Introducing Klein, a small ORM that used immutable data for models.

Defining a model is as simple as telling Klein the name of the table:

const Klein = require('klein/auto');

const Things = Klein.model('things');

Then you can query it using methods similar to straight knex:

Things.all().then(things => {
    // things is an Immutable.List()
    console.log(things);
});

Things.where({ some_field: 'some value' }).first().then(thing => {
    // thing is an Immutable.Map()
    console.log(thing);
});

As each model 'instance' is simply an instance of Immutable, all ORM methods are performed from the model's class:

let cat = Immutable.Map({
    name: 'Cat',
    says: 'Meow'
});

Things.save(cat).then(cat => {
    // cat is an instance of Immutable.Map() and now has id, created_at, and updated_at fields
    cat = cat.set('says', 'MEOW!!');

    return Things.save(cat);
}).then(cat => {
    // cat is an instance of Immutable.Map() and now says 'MEOW!!'
    console.log(cat);
});

For more (up to date) information read the Klein docs.

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