Generate combinations using elements from an array

combinate.js

function combinations(options,places) {
	// options is array
	// places is positive int
	
	if (places <= 1) {
		let c = []
		for (let o of options) {
			c.push([o])
		}

		return c
	}
	else {
		let c = []

		for (let o of options) {
			for (let subc of combinations(options,places-1)) {
				c.push([o].concat(subc))
			}
		}

		return c
	}
}

// example

combinations('abcde',2) // --> 'a','a' 'a','b' 'a','c' ...