Question

How to remove the letters from word1 if they do not exist in word2 with JavaScript

Answer 1

function removeNonCommonLetters(word1, word2) {
  let result = '';
  
  for (let char of word1) {
    if (word2.includes(char)) {
      result += char;
    }
  }
  
  return result;
}

const word1 = "forest";
const word2 = "tor";

const result = removeNonCommonLetters(word1, word2);

console.log(result);



/*
run:

ort

*/

 

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Answer 2

function removeNonCommonLetters(word1, word2) {
    const word2Set = new Set(word2);
    
    return word1
        .split('')
        .filter(char => word2Set.has(char))
        .join('');
}

const word1 = "forest";
const word2 = "tor";

const result = removeNonCommonLetters(word1, word2);

console.log(result);



/*
run:

ort

*/

 

70+ SQL courses for beginners and professionals

Answer 3

const removeNonCommonLetters = (word1, word2) => 
    [...word1].filter(char => word2.includes(char)).join('');

const word1 = "forest";
const word2 = "tor";

const result = removeNonCommonLetters(word1, word2);

console.log(result);



/*
run:

ort

*/

 

70+ SQL courses for beginners and professionals