longest-prefix-naive-solution.js

function longestPrefix(words) {
    if (words.length == 0) return `""`;
    
    const longestPossiblePrefixSize = Math.min(...words.map(word => word.length))

    for (let prefixSize = longestPossiblePrefixSize; prefixSize > 0; prefixSize--) {
        const [ firstWord, ...otherWords ] = words

        if (otherWords.every(word => word.substr(0, prefixSize) == firstWord.substr(0, prefixSize))) {
            return `"${firstWord.substr(0, prefixSize)}"`;
        }
    }

    return `""`;
}

console.log(
    longestPrefix(['flower', 'flow', 'flight'])
)

console.log(
    longestPrefix(['dog', 'racecar', 'car'])
)