Very simple javascript list class

gistfile1.js

var DataList = function(el, data, itemTpl, populateItemDataFn) {
	if (! (el instanceof Node)) {
		throw new Error('el should be an Node.');
	}
	if (! (data instanceof Array)) {
		throw new Error('data should be an Array.');
	}
	if (typeof itemTpl !== 'string') {
		throw new Error('itemTpl should be an String.');
	}
	if (typeof populateItemDataFn !== 'undefined' && ! (populateItemDataFn instanceof Function)) {
		throw new Error('populateItemDataFn should be an Function.');
	}
	this.el = el;
	this.data = data;
	this.itemTpl = itemTpl;
	this.populateItemDataFn = populateItemDataFn;
	this.render();
};

DataList.prototype = {
	el: null,
	itemTpl: '',
	data: [],
	populateItemDataFn: null,
	render: function() {
		if (! this.el) {
			return;
		}
		this.el.innerHTML = '';
		for (var i=0,ln=this.data.length; i<ln; i++) {
			this.el.appendChild(this.makeItem(this.data[i]));
		}
	},
	update: function(data) {
		if (! (data instanceof Array)) {
			throw new Error('data should be an Array.');
		}
		this.data = data;
		this.render();
	},
	makeItem: function(itemData) {
		var itemEl = document.createElement('DIV');
		itemEl.innerHTML = this.itemTpl;
		if (this.populateItemDataFn) {
			this.populateItemDataFn(itemEl, itemData);
		}
		return itemEl;
	}
};
	

// How to use

window.notifyList = new DataList(
	document.getElementById('notify'),
	[],
	document.getElementById('notify-item-tpl').innerHTML, function(itemEl, itemData) {
		var containerEl = itemEl.querySelector('[data-container]');
		var userEl = itemEl.querySelector('[data-user]');
		var userImageEl = itemEl.querySelector('[data-user-image]');
		var userNameEl = itemEl.querySelector('[data-user-name]');
		var textEl = itemEl.querySelector('[data-text]');
		var actionEl = itemEl.querySelector('[data-action]');
		containerEl.classList.add('notify-item-new');
		userNameEl.innerHTML = itemData.name;
		textEl.innerHTML = 'Hello, world';
		actionEl.innerHTML = '<a class="btn btn-primary" href="#">Follow</a>';
	}
);

window.notifyList.update([
	{ name: 'Hello' },
	{ name: 'Bro' }
]);