icedam


Friends don't let friends mutate.

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Ice Dam: a very lightweight library to freeze data. Data is frozen at the __edge__, where your Flux container sends it to views.

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To prevent accidental mutation and bugs.

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For Redux, you wrap a component in a connect function. Its first argument is a selector.

``
function mapStateToProps(state) {
return {
products: state.products
};
}

var App = connect(mapStateToProps)(App)
`

Adding __freeze__ will call Object.freeze in development

npm install --save icedam

`
import {makeFreezer} from 'icedam';
var freeze = makeFreezer();

function mapStateToProps(state) {
return freeze({
products: state.products
});
}

var App = connect(mapStateToProps)(App)
`

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Screencast

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Using an immutable library means commiting to using it throughout your stack. You'll have to change coding style, teach all your developers, and call toJS() when passing data. If your only concern is preventing views from mutating data, that might be too much.

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In production: No cost. No freezing.

In dev (process.env.NODE_ENV === 'development'`): when data structures change, cloning has a slight cost, usually well under a millisecond.

IceDam only clones objects when they have changed (!shallowEqual).

Image Credit: skekonk