| 1 | /**
|
| 2 | * @prototype Range
|
| 3 | *
|
| 4 | * Helper class to make working with related min and max values easier.
|
| 5 | *
|
| 6 | * The range is inclusive; a given value is considered part of the range if:
|
| 7 | *
|
| 8 | * this.min <= value <= this.max
|
| 9 | */
|
| 10 | function Range() {
|
| 11 | this.min = undefined;
|
| 12 | this.max = undefined;
|
| 13 | }
|
| 14 |
|
| 15 |
|
| 16 | /**
|
| 17 | * Adjust the range so that the passed value fits in it.
|
| 18 | *
|
| 19 | * If the value is outside of the current extremes, adjust
|
| 20 | * the min or max so that the value is within the range.
|
| 21 | *
|
| 22 | * @param {number} value Numeric value to fit in range
|
| 23 | */
|
| 24 | Range.prototype.adjust = function(value) {
|
| 25 | if (value === undefined) return;
|
| 26 |
|
| 27 | if (this.min === undefined || this.min > value ) {
|
| 28 | this.min = value;
|
| 29 | }
|
| 30 |
|
| 31 | if (this.max === undefined || this.max < value) {
|
| 32 | this.max = value;
|
| 33 | }
|
| 34 | };
|
| 35 |
|
| 36 |
|
| 37 | /**
|
| 38 | * Adjust the current range so that the passed range fits in it.
|
| 39 | *
|
| 40 | * @param {Range} range Range instance to fit in current instance
|
| 41 | */
|
| 42 | Range.prototype.combine = function(range) {
|
| 43 | this.add(range.min);
|
| 44 | this.add(range.max);
|
| 45 | };
|
| 46 |
|
| 47 |
|
| 48 | /**
|
| 49 | * Expand the range by the given value
|
| 50 | *
|
| 51 | * min will be lowered by given value;
|
| 52 | * max will be raised by given value
|
| 53 | *
|
| 54 | * Shrinking by passing a negative value is allowed.
|
| 55 | *
|
| 56 | * @param {number} val Amount by which to expand or shrink current range with
|
| 57 | */
|
| 58 | Range.prototype.expand = function(val) {
|
| 59 | if (val === undefined) {
|
| 60 | return;
|
| 61 | }
|
| 62 |
|
| 63 | var newMin = this.min - val;
|
| 64 | var newMax = this.max + val;
|
| 65 |
|
| 66 | // Note that following allows newMin === newMax.
|
| 67 | // This should be OK, since method expand() allows this also.
|
| 68 | if (newMin > newMax) {
|
| 69 | throw new Error('Passed expansion value makes range invalid');
|
| 70 | }
|
| 71 |
|
| 72 | this.min = newMin;
|
| 73 | this.max = newMax;
|
| 74 | };
|
| 75 |
|
| 76 |
|
| 77 | /**
|
| 78 | * Determine the full range width of current instance.
|
| 79 | *
|
| 80 | * @returns {num} The calculated width of this range
|
| 81 | */
|
| 82 | Range.prototype.range = function() {
|
| 83 | return this.max - this.min;
|
| 84 | };
|
| 85 |
|
| 86 |
|
| 87 | /**
|
| 88 | * Determine the central point of current instance.
|
| 89 | *
|
| 90 | * @returns {number} the value in the middle of min and max
|
| 91 | */
|
| 92 | Range.prototype.center = function() {
|
| 93 | return (this.min + this.max) / 2;
|
| 94 | };
|
| 95 |
|
| 96 |
|
| 97 | module.exports = Range;
|