var is = require('./is');
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var delegate = require('delegate');
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/**
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* Validates all params and calls the right
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* listener function based on its target type.
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*
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* @param {String|HTMLElement|HTMLCollection|NodeList} target
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* @param {String} type
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* @param {Function} callback
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* @return {Object}
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*/
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function listen(target, type, callback) {
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if (!target && !type && !callback) {
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throw new Error('Missing required arguments');
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}
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if (!is.string(type)) {
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throw new TypeError('Second argument must be a String');
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}
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if (!is.fn(callback)) {
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throw new TypeError('Third argument must be a Function');
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}
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if (is.node(target)) {
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return listenNode(target, type, callback);
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}
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else if (is.nodeList(target)) {
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return listenNodeList(target, type, callback);
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}
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else if (is.string(target)) {
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return listenSelector(target, type, callback);
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}
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else {
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throw new TypeError('First argument must be a String, HTMLElement, HTMLCollection, or NodeList');
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}
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}
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/**
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* Adds an event listener to a HTML element
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* and returns a remove listener function.
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*
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* @param {HTMLElement} node
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* @param {String} type
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* @param {Function} callback
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* @return {Object}
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*/
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function listenNode(node, type, callback) {
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node.addEventListener(type, callback);
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return {
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destroy: function() {
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node.removeEventListener(type, callback);
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}
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}
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}
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/**
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* Add an event listener to a list of HTML elements
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* and returns a remove listener function.
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*
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* @param {NodeList|HTMLCollection} nodeList
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* @param {String} type
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* @param {Function} callback
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* @return {Object}
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*/
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function listenNodeList(nodeList, type, callback) {
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Array.prototype.forEach.call(nodeList, function(node) {
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node.addEventListener(type, callback);
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});
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return {
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destroy: function() {
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Array.prototype.forEach.call(nodeList, function(node) {
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node.removeEventListener(type, callback);
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});
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}
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}
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}
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/**
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* Add an event listener to a selector
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* and returns a remove listener function.
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*
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* @param {String} selector
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* @param {String} type
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* @param {Function} callback
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* @return {Object}
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*/
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function listenSelector(selector, type, callback) {
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return delegate(document.body, selector, type, callback);
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}
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module.exports = listen;
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