Generating interesting variants on a classic Dr. Seuss poem with a quick and dirty script

old_gold_hold.js

//
// SO copy-pasta
//
function perm(xs) {
  let ret = [];

  for (let i = 0; i < xs.length; i = i + 1) {
    let rest = perm(xs.slice(0, i).concat(xs.slice(i + 1)));

    if(!rest.length) {
      ret.push([xs[i]])
    } else {
      for(let j = 0; j < rest.length; j = j + 1) {
        ret.push([xs[i]].concat(rest[j]))
      }
    }
  }
  return ret;
}

// fuck it, let's live dangerously and slow.
String.prototype.replaceAll = function(search, replacement) {
    var target = this;
    return target.replace(new RegExp(search, 'g'), replacement);
};

//
//
//

const story = `My N0 is A0, my N1 are A1.
I have a N2 I like to hold.
My N3 is A2, my N4 is A3.
My N3 is A2, my N4 is A3.
I have a N2 I like to hold.
My N0 is A0, my N1 are A1.
And now my story is all told.`

const nouns = ["hat", "teeth", "bird", "shoe", "foot"]
const adjectives = ["old", "gold", "off", "cold"]

const nPerms = perm(nouns)
const aPerms = perm(adjectives)


let output = ""
let sep = ""
for (let i = 0; i < nPerms.length; i += 1) {
	outer: 
	for (let j = 0; j < aPerms.length; j += 1) {
		output += sep
		
		const ns = nPerms[i]
		const as = aPerms[j]

		for (let k = 0; k < ns.length; k += 1) {
			if (ns[k] === nouns[k]) continue outer
		}
		for (let k = 0; k < as.length; k += 1) {
			if (as[k] === adjectives[k]) continue outer
		}
		
		
		let str = story
		
		for (let k = 0; k < ns.length; k += 1) {
			str = str.replaceAll("N" + k, ns[k])
		}
		for (let k = 0; k < as.length; k += 1) {
			str = str.replaceAll("A" + k, as[k])
		}
		
		output += str

		sep = "\n\n"
	}
}

console.log(output)