1 require("../env");

     2 require("../../d3");

     3 

     4 var vows = require("vows"),

     5     assert = require("assert");

     6 

     7 var suite = vows.describe("d3.first");

     8 

     9 suite.addBatch({

    10   "first": {

    11     topic: function() {

    12       return d3.first;

    13     },

    14     "compares using natural order by default": function(first) {

    15       assert.strictEqual(first([1, 0]), 0);

    16       assert.strictEqual(first(["1", 0]), 0);

    17       assert.strictEqual(first(["2", "10"]), "10");

    18       assert.strictEqual(first(["2", NaN, "10"]), "10");

    19       assert.strictEqual(first([2, NaN, 10]), 2);

    20     },

    21     "compares using optional comparator": function(first) {

    22       var i = 0, aa, bb, o = new Object();

    23       assert.strictEqual(first([1, o], function(a, b) { aa = a; bb = b; return ++i; }), o);

    24       assert.strictEqual(aa, 1);

    25       assert.strictEqual(bb, o);

    26       assert.strictEqual(first([1, 0], d3.descending), 1);

    27       assert.strictEqual(first(["1", 0], d3.descending), "1");

    28       assert.strictEqual(first(["2", "10"], d3.descending), "2");

    29       assert.strictEqual(first(["2", NaN, "10"], d3.descending), "2");

    30       assert.strictEqual(first([2, NaN, 10], d3.descending), 10);

    31     },

    32     "returns the first of equal values": function(last) {

    33       var a = new Object(), b = new Object(), c = new Object();

    34       assert.strictEqual(last([a, b, c], function() { return 0; }), a);

    35     },

    36     "returns undefined for an empty array": function(first) {

    37       assert.isUndefined(first([]));

    38     }

    39   }

    40 });

    41 

    42 suite.export(module);