navigation-traversal-methods.js

const _containsActiveClass = function( _el, i ) {
	
	for ( ; i < _el.children.length; i++ ) {

		if ( _el.children[ i ].children[ 0 ] ) {
			return _containsActiveClass( _el.children[ i ], 0 )
		}

		return _el.children[ i ].classList.contains( ACTIVE_CLASS )

	}

}

const _findNestedSiblings = ( _el ) => {

	    let matches = []

	    let parent = _el.parentNode

	    for ( let i = 0; i < parent.children.length; i++ ) {
	      let child = parent.children[ i ]
	        if (child !== _el && 
	            child.nodeType === 1) {
	        	if ( child.children[0] && 
	        		child.children[0].tagName === "A" ) {
		            matches.push( child.children[0] )
		        }
	        }
	    }

	    return matches
	}
  
  	const _filterChildElement     = function( _el, item ) {
					
		for ( let i = 0; i < _el.children.length; i++ ) {
			if ( _el.children[ i ] === item) {
				return true;
			}
		}

		return false;
	}