boggle.js

function getNbs(i,j, board){
   let coords = []
  

   for (let ii = i-1; ii<= i+1; ii++){
     for (let jj = j-1; jj<= j+1; jj++){
        const inbound = ii >= 0 && ii < board.length && jj >= 0 && jj < board[0].length
        if (inbound){
          coords.push([ii, jj])
        }
     }
   }
    return coords
 }


function boggle(board, word){
   
   if (word.length === 0) return false
   
   const firstLetter = word[0]
   
   let visited = Array.from({ length: board.length}, e => Array.from({ length: board[0].length }, e => false ))
     
   for (let i = 0; i< board.length; i++){
        for(let j=0; j< board[i].length;j++){
            const letter = board[i][j]
              if (letter === firstLetter){
                  console.log("Letter:", [i,j])
                  if (dfs([i,j], word, visited)){
                    return true
                  }
              }
        }
   }
  
  
  function dfs(letterCoordinate, word, visited){
    
    console.log(visited)

     let foundWord = false

     function helper(letterCoordinate, word, index){

  
        const [i,j] = letterCoordinate
        
        if (foundWord){
          return
        }
                  
         if (index === word.length -1 ){
           console.log('index === word.length')
           foundWord = true
           return
         }
       
        console.log({letter: board[i][j], index})
      
         visited[i][j] = true
       
         const nbs = getNbs(i,j, board)

         const idealNeighborLetter = word[index+1]

         for (let neighbor of nbs){

             const [nI,nJ] = neighbor
             const letterNeighbor = board[nI][nJ]
             const neighborVisited = visited[nI][nJ]

             if (!neighborVisited && letterNeighbor === idealNeighborLetter){
                 console.log('letterNeighbor', letterNeighbor)
                 helper(neighbor, word,  index+1) 
             }
         }
       
         visited[i][j] = false
     }

     helper(letterCoordinate, word, 0)

     return foundWord

 }
  
  return false
}

const board = [['N', 'P', 'E', 'I', 'C', 'E'],
         ['S', 'O', 'U', 'P', 'R', 'U'],
         ['I', 'P', 'O', 'U', 'A', 'U'],
         ['I', 'B', 'S', 'Y', 'S', 'X']
      ]
  
boggle(board, "SOUPE")