const words = ["react", "angular", "react", "react", "redux"];

const initialObject = {};

const word = words.reduce(
  (acc, word) => {
    if (!acc[word]) {
      acc[word] = 1;
    } else {
      acc[word]++;
    }
    return acc;
  },
  initialObject
);

console.log(word);

//output
initialObject { react: 3, angular: 1, redux: 1 };