consecutive strings.js

// Concatenate the consecutive strings of strarr by 2, we get:

// treefoling   (length 10)  concatenation of strarr[0] and strarr[1]
// folingtrashy ("      12)  concatenation of strarr[1] and strarr[2]
// trashyblue   ("      10)  concatenation of strarr[2] and strarr[3]
// blueabcdef   ("      10)  concatenation of strarr[3] and strarr[4]
// abcdefuvwxyz ("      12)  concatenation of strarr[4] and strarr[5]

// Two strings are the longest: "folingtrashy" and "abcdefuvwxyz".
// The first that came is "folingtrashy" so 
// longest_consec(strarr, 2) should return "folingtrashy".

// In the same way:
// longest_consec(["zone", "abigail", "theta", "form", "libe", "zas", "theta", "abigail"], 2) --> "abigailtheta"
// n being the length of the string array, if n = 0 or k > n or k <= 0 return "" (return Nothing in Elm, "nothing" in Erlang).

// Note
// consecutive strings : follow one after another without an interruption


function longestConsec(strarr, k) {
    if(strarr.length == 0 || k>strarr.length || k<= 0){
      return ''
    }
    let concatenatedArr = []
    let currentWord = ''
    for (let i = 0; i < strarr.length; i++) {
      for (let j = 0; j < k && i+j<strarr.length; j++){
        currentWord += strarr[i+j]
      }
      concatenatedArr.push(currentWord)
      currentWord = ''
    }
    let concatenatedArrLength = concatenatedArr.map(x=> x.length)
    let targetIndex = concatenatedArrLength.indexOf(Math.max(...concatenatedArrLength))
    return concatenatedArr[targetIndex]
}