Generators

numbers.js

// Basic usage of using generators
function *numbers() {
  yield 1;
  yield 2;
  yield* moreNumbers();
  yield 6;
  yield 7;
}

function *moreNumbers() {
  yield 3;
  yield 4;
  yield 5;
}

const generator = numbers();

let values = [];

for (let value of generator) {
  values.push(value);
}

// Log will produces [1,2,3,4,5,6,7]
console.log(values);

Tree.js

class Tree {
	constructor(value = null, children = []) {
		this.value = value;
		this.children = children;
	}
	
	*printValues() {
		yield this.value;
		
		for (let child of this.children) {
			yield* child.printValues();
		}
		
	}
}

const tree = new Tree(1, [
	new Tree(2, [new Tree(4)]),
	new Tree(3)
]);

// We can now collect all the values of the tree as such
const values = [];

for (let value of tree.printValues()) {
	values.push(value);
}

console.log(values);