is-valid-traffic-lights-sequence.js

const pattern = ["red", "green", "yellow"];

function isValidTrafficSequence(matcher: string[]) {
  const target = new Array(matcher.length).fill(pattern).flatMap(x => x);
  const reducer = (acc: [], item: never, index: number) => {
   if (item === target[index])  acc.push(item);
   return acc;
 }
  
  const result = matcher.reduce(reducer, []);

  return matcher.length === result.length;
}

isValidTrafficSequence(["red", "green", "yellow", "red", "green"]);
isValidTrafficSequence(["red", "yellow", "green"]);
isValidTrafficSequence([]);

isValidTrafficSequence(["red", "yellow", "green", "red", "yellow", "green", "red", "yellow", "green", "green"]);

A simple task for validating a traffic light 🚦 sequence, I've got from a challenge of the week.