ArrayMethodsAndTests/fill.html at master · joshmerritt/ArrayMethodsAndTests · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
<script src="../simpletest.js"></script>
<script>

/* Prototype function
    function fill(originalArray, value, start, end) {
        var startPos = 0;
        var endPos = originalArray.length;
        if(arguments.length > 2) {
          startPos = start;
        }
        if(arguments.length > 3) {
          endPos = end;
        }
        for(var i = startPos; i < endPos; i++) {
          originalArray[i] = value;
        }
        return originalArray;
    }
*/

function fill(originalArray, value, start, end) {
      var startPos = 0;
      var endPos = originalArray.length;
      if(arguments.length > 2) {
        if(start < 0) {
          startPos = originalArray.length + start;
        }
        else {
          startPos = start;
        }
      }
      if(arguments.length > 3) {
        if(end < 0) {
          endPos = originalArray.length + end;
        }
        else {
          endPos = end;
        }
      }
      for(var i = startPos; i < endPos; i++) {
        originalArray[i] = value;
      }
      return originalArray;
  }


tests({

  'It should return an array': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6);
    eq(Array.isArray(returnResult),true);
  },

  'It should modify the original array': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6);
    eq(testArray[0],6);
  },

  'It should accept an optional starting position': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6, 1);
    eq(testArray[0],1);
    eq(testArray[1],6);
    eq(testArray[2],6);
  },

  'It should accept an optional end position': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6, 0, 1);
    eq(testArray[0],6);
    eq(testArray[1],2);
    eq(testArray[2],3);
  },

  'It should default to 0 if no starting position is provided': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6);
    eq(testArray[0],6);
    eq(testArray[1],6);
    eq(testArray[2],6);
  },

  'It should default to original array length if no end position is provided': function () {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6, 1);
    eq(testArray[0],1);
    eq(testArray[1],6);
    eq(testArray[2],6);
  },

  'If start provided is negative, it acts as an offset from the end of the array': function() {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6, -1);
    eq(testArray[0],1);
    eq(testArray[1],2);
    eq(testArray[2],6);
  },

  'If end provided is negative, it acts as an offset from the end of the array': function() {
    var testArray = [1,2,3];
    var returnResult = fill(testArray, 6, 0, -1);
    eq(testArray[0],6);
    eq(testArray[1],6);
    eq(testArray[2],3);
  }

});

</script>