nested iteration, global palette accumulated from children

palattegen.js

var paletteMap = {};
var palette = [];

//Iterate over child voxel meshes
Qbjson.matrixList.map((Mesh) => {
  var x = Mesh.sizeX;
  var y = Mesh.sizeY;
  var z = Mesh.sizeZ;
  
  var n = ndarray(
    new Int32Array(x * y * z),
    [x, y, z]
  );
  
  var paletteIndex;
  // Iterate over each voxel in the voxel mesh push the voxel colors to the global palette
  Mesh.matrix.forEach(function(voxel){
    var r = voxel.r / 255;
    var g = voxel.g / 255;
    var b = voxel.b / 255;
    
    if(paletteMap[r] === undefined){
      paletteMap[r] = {};
    }
    
    if(paletteMap[r][g] === undefined){
      paletteMap[r][g] = {};
    }
    
    if(paletteMap[r][g][b] === undefined){
      palette.push([r,g,b, 1.0]);
      paletteIndex = palette.length;
      paletteMap[r][g][b] = paletteIndex;
    }else{
      paletteIndex = paletteMap[r][g][b];      
    }
    
    //Push each voxel coord to the Ndarray
    n.set(
      voxel.x,
      voxel.y,
      voxel.z,
      paletteIndex
    );    
  });
  
  
  return {
    ndvoxels: n,
    offset: [Mesh.posX, Mesh.posY, Mesh.posZ],
    name: Mesh.name
  }
});