var nest = require('nest');
var assert = require('assert');

var eq = assert.deepEqual;

// input data to be nested
var data = [
  { type: "apple", color: "green", quantity: 1000 }, 
  { type: "apple", color: "red", quantity: 2000 }, 
  { type: "grape", color: "green", quantity: 1000 }, 
  { type: "grape", color: "red", quantity: 4000 }
];


/* FIRST EXAMPLE */

// expected output, grouping by `color` and `quantity`
var expected = {
  green: {
    "1000": [
      { type: 'apple', color: 'green', quantity: 1000 }, 
      { type: 'grape', color: 'green', quantity: 1000 }
    ]
  },
  red: {
    "2000": [
      { type: 'apple', color: 'red', quantity: 2000 }
    ],
    "4000": [
      { type: 'grape', color: 'red', quantity: 4000 }
    ]
  }
};


// key functions used for grouping criteria

var byType = function(d) {
  return d.type;
};

var byColor = function(d) {
  return d.color;
};

var byQuantity = function(d) {
  return d.quantity;
};


// nest by key name
eq(nest(data, ['color', 'quantity']), expected);

// nest by key function
eq(nest(data, [byColor, byQuantity]), expected);



/* SECOND EXAMPLE */

// expected output, grouping by `type` and `color`
expected = {
  apple: {
    green: [ { "type": "apple", "color": "green", "quantity": 1000 } ],
    red: [ { "type": "apple", "color": "red", "quantity": 2000 } ]
  },
  grape: {
    green: [ { "type": "grape", "color": "green", "quantity": 1000 } ],
    red: [ { "type": "grape", "color": "red", "quantity": 4000 } ]
  }
};

// nest by key names
eq(nest(data, ['type', 'color']), expected);

// nest by key function
eq(nest(data, [byType, byColor]), expected);