Javascript Algorithm Array Validate sudoku

'use  strict';/*from  w  w  w .  j av  a  2 s  .co m*/

var _ = require('underscore');

var good_sudoku = [ [7,8,4,1,5,9,3,2,6], 
              [5,3,9,6,7,2,8,4,1], 
              [6,1,2,4,3,8,7,5,9], 
              [9,2,8,7,1,5,4,6,3], 
              [3,5,7,8,4,6,1,9,2], 
              [4,6,1,9,2,3,5,8,7], 
              [8,7,6,3,9,4,2,1,5], 
              [2,4,3,5,6,1,9,7,8], 
              [1,9,5,2,8,7,6,3,4] 
             ];

// part 1 - all rows have unique digits 1-9

// part 2 - all columns have unique digits 1-9

// part 3 - every 3x3 matrix (there are 9) have unique digits 1-9
function rowCheck (array) {
  // Explicitly building object for easier reference
  var possibleValues = {
    1: false,
    2: false,
    3: false,
    4: false,
    5: false,
    6: false,
    7: false,
    8: false,
    9: false
  }
  
  for(var i = 0; i < array.length; i++) {
    if(possibleValues[array[i]])
       return false
       
    if(!possibleValues[array[i]])
      possibleValues[array[i]] = true
  }
  
  for (var key in possibleValues) {
    if(possibleValues[key] === false)
      return false
  }
  
  return true
}
// mapping vertical rows for easier reference 
function buildVerticalRows(matrix) {
  var flippedRows = []
  var currentRow = 0
  
  while(currentRow < 9 ){
    if(currentRow === 0) {
      matrix[currentRow].forEach(function(num) {
        flippedRows.push([num])
      })
      currentRow++
      continue
    }
    
    for(var i = 0; i < matrix[currentRow].length; i++) {
      flippedRows[i].push(matrix[currentRow][i])
    }
    currentRow++
  }
  return flippedRows
}

function buildSectors(matrix) {
  var sectorTop = 0
  var sectors = []
  var currentSectorLevel
  
  while(sectorTop < 9) {
    for(var i = 0; i < 3; i++) {
      currentSectorLevel = sectorTop + i

      if(i === 0) {
        sectors.push(matrix[currentSectorLevel].slice(0,3))
        sectors.push(matrix[currentSectorLevel].slice(3,6))
        sectors.push(matrix[currentSectorLevel].slice(6,9))
        continue
      }

      sectors[sectorTop + 0] = sectors[sectorTop + 0].concat(matrix[currentSectorLevel].slice(0,3))
      sectors[sectorTop + 1] = sectors[sectorTop + 1].concat(matrix[currentSectorLevel].slice(3,6))
      sectors[sectorTop + 2] = sectors[sectorTop + 2].concat(matrix[currentSectorLevel].slice(6,9))
    }
    sectorTop += 3
  }
  
  return sectors
}
// console.log(buildSectors(good_sudoku))

function validateSudoku(matrix) {
  var validators = [
    function(matrix) {return matrix},
    buildVerticalRows,
    buildSectors
  ]

  for (var i = 0; i < validators.length; i++) {

    var currentMatrix = validators[i](matrix)
    for(var i = 0; i < currentMatrix.length; i++) {
      if(!rowCheck(currentMatrix[i]))
        return false
    }
  }
  return true
}

// console.log(validateSudoku(good_sudoku))