JS solution to CodeSignal isCryptSolution exercise.

isCryptSolution.js

function isCryptSolution(crypt, solution) {
    let hasLeadingZeros = false;
    const decrypted = crypt.map(word => {
        const number = word.split('').map(letter => {
            return solution.find(key => key[0] === letter)[1];
        }).join('');
        
        if (number.startsWith('0') && number.length > 1) {
            hasLeadingZeros = true;
        }
        
        return Number.parseInt(number);
    });
    
    
    return !hasLeadingZeros && decrypted[0] + decrypted[1] === decrypted[2];
}

/* A cryptarithm is a mathematical puzzle for which the goal is to find the 
correspondence between letters and digits, such that the given arithmetic 
equation consisting of letters holds true when the letters are converted to digits.

You have an array of strings crypt, the cryptarithm, and an an array containing 
the mapping of letters and digits, solution. The array crypt will contain 
three non-empty strings that follow the structure: [word1, word2, word3], which 
should be interpreted as the word1 + word2 = word3 cryptarithm.

If crypt, when it is decoded by replacing all of the letters in the cryptarithm 
with digits using the mapping in solution, becomes a valid arithmetic equation 
containing no numbers with leading zeroes, the answer is true. If it does not 
become a valid arithmetic solution, the answer is false. */