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Fix rounding issue with the precision param of _.floor.

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This commit is contained in:
Tejo Kumar Reddy Chenchu
2015-09-24 01:12:13 -07:00
committed by John-David Dalton
parent 3fd276f8a6
commit dd27a0adc7
2 changed files with 37 additions and 12 deletions
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11
lodash.js
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@@ -4081,8 +4081,15 @@
return function(number, precision) {
precision = precision ? toInteger(precision) : 0;
if (precision) {
precision = pow(10, precision);
return func(number * precision) / precision;
// Shift the decimal point with exponential notation to avoid floating-point funny bussiness.
// See [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round#Examples)
// for more details.
var pair = (+number + 'e').split('e'),
value = func(pair[0] + 'e' + (+pair[1] + precision));
// Shift back.
pair = (value + 'e').split('e');
return +(pair[0] + 'e' + (pair[1] - precision));
}
return func(number);
};

38
test/test.js
View File

@@ -11362,6 +11362,7 @@
}
});
}());
/*--------------------------------------------------------------------------*/
QUnit.module('lodash.mapKeys');
@@ -16222,13 +16223,30 @@
assert.strictEqual(actual, isCeil ? 5 : 4);
});
QUnit.test('`_.' + methodName + '` should return a rounded number with a precision of `0`', function(assert) {
QUnit.test('`_.' + methodName + '` should work with a precision of `0`', function(assert) {
assert.expect(1);
var actual = func(4.006, 0);
assert.strictEqual(actual, isCeil ? 5 : 4);
});
QUnit.test('`_.' + methodName + '` should work with a positive precision', function(assert) {
assert.expect(2);
var actual = func(4.016, 2);
assert.strictEqual(actual, isFloor ? 4.01 : 4.02);
actual = func(4.1, 2);
assert.strictEqual(actual, 4.1);
});
QUnit.test('`_.' + methodName + '` should work with a negative precision', function(assert) {
assert.expect(1);
var actual = func(4160, -2);
assert.strictEqual(actual, isFloor ? 4100 : 4200);
});
QUnit.test('`_.' + methodName + '` should coerce `precision` to an integer', function(assert) {
assert.expect(3);
@@ -16244,18 +16262,18 @@
assert.strictEqual(actual, expected);
});
QUnit.test('`_.' + methodName + '` should return a rounded number with a positive precision', function(assert) {
assert.expect(1);
QUnit.test('`_.' + methodName + '` should work with exponential notation and `precision`', function(assert) {
assert.expect(3);
var actual = func(4.016, 2);
assert.strictEqual(actual, isFloor ? 4.01 : 4.02);
});
var actual = func(5e1, 2);
assert.deepEqual(actual, 50);
QUnit.test('`_.' + methodName + '` should return a rounded number with a negative precision', function(assert) {
assert.expect(1);
actual = func('5e', 1);
assert.deepEqual(actual, NaN);
actual = func('5e1e1', 1);
assert.deepEqual(actual, NaN);
var actual = func(4160, -2);
assert.strictEqual(actual, isFloor ? 4100 : 4200);
});
});