const tree = {
	left:{
		left: {
			left:{
				left: {},
				right: {}
			},
		},
		right: {}
	},
	right: {
		left: {},
		right: {
			left: {},
			right: {}
		}
	}
}

const paths = [];
let currPath = '';
const traverse = (node)=>{
	if(node.left === undefined && node.right === undefined){
		paths.push(currPath)
	}	
	if(node.left){
		currPath += 'l';
		traverse(node.left)
	}
	if(node.right){
		currPath += 'r';
		traverse(node.right)
	}
	currPath = currPath.substring(0, currPath.length-1);
}

traverse(tree)
console.log(paths);