Triggers for Redux - perform imperative actions & dispatches on specific changes in the store w/o touching React components

gistfile1.txt

import {bindActionCreators} from 'redux';

export function withSelectors(...selectors) {
	const bound = selectors.pop();
	return (...args) => {
		const state = args[args.length-1].getState();
		return bound(...selectors.map( sel => sel(state) ), ...args);
	}
}

export function withActions(...actions) {
	const bound = actions.pop();
	return (...args) => {
		const {dispatch} = args[args.length-1];
		return bound(...actions.map( act => bindActionCreators(act, dispatch) ), ...args);
	}
}

export function createTrigger(selector, trigger, hasChanged= (next, last) => last!==next) {
	let lastValue;
	return store => {
		const newValue = selector(store.getState());
		if(hasChanged(newValue, lastValue)) {
			const copyLastValue = lastValue;
			lastValue = newValue;
			trigger(newValue, copyLastValue, store);
		}
	}
}

export function bindTriggers(store, triggers, onerror= err => {throw err}) {
	return store.subscribe(
		() => triggers.forEach(
			trigger => {
				try { trigger(store) } catch(err) { onerror(err, trigger) }
			}
		)
	);
}