ensure that rounding rounds half up (#102)

scurker · Apr 9, 2018 · 347bd3c · 347bd3c
1 parent 212624c
commit 347bd3c
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Showing 2 changed files with 31 additions and 14 deletions.
diff --git a/src/currency.js b/src/currency.js
@@ -53,22 +53,19 @@ function currency(value, opts) {
 function parse(value, opts, useRounding = true) {
   let v = 0
     , { decimal, errorOnInvalid, precision: decimals } = opts
-    , precision = pow(decimals);
+    , precision = pow(decimals)
+    , isNumber = typeof value === 'number';
 
-  if (typeof value === 'number') {
-    v = value * precision;
-  } else if (value instanceof currency) {
-    v = value.value * precision;
-  } else if (typeof(value) === 'string') {
+  if (isNumber || value instanceof currency) {
+    v = ((isNumber ? value : value.value) * precision).toFixed(1);
+  } else if (typeof value === 'string') {
     let regex = new RegExp('[^-\\d' + decimal + ']', 'g')
       , decimalString = new RegExp('\\' + decimal, 'g');
-    v = parseFloat(
-          value
-            .replace(/\((.*)\)/, '-$1')   // allow negative e.g. (1.99)
-            .replace(regex, '')           // replace any non numeric values
-            .replace(decimalString, '.')  // convert any decimal values
-            * precision                   // scale number to integer value
-        );
+    v = value
+          .replace(/\((.*)\)/, '-$1')   // allow negative e.g. (1.99)
+          .replace(regex, '')           // replace any non numeric values
+          .replace(decimalString, '.')  // convert any decimal values
+          * precision;                  // scale number to integer value
     v = v || 0;
   } else {
     if(errorOnInvalid) {

diff --git a/test/test.js b/test/test.js
@@ -79,6 +79,26 @@ test('should subtract floating point', t => {
   t.not(parseFloat(value), 2.52-.01, 'currency(2.52).subtract(.01) does not equal 2.5100000000000002');
 });
 
+test('should round half up', t => {
+  var value1 = currency(17.955)
+    , value2 = currency(17.855)
+    , value3 = currency(17.455);
+
+  t.is(value1.value, 17.96, 'currency(17.955) rounds half up to 17.96');
+  t.is(value2.value, 17.86, 'currency(17.855) rounds half up to 17.86');
+  t.is(value3.value, 17.46, 'currency(17.955) rounds half up to 17.46');
+});
+
+test('should round negative values half up', t => {
+  var value1 = currency(-17.955)
+    , value2 = currency(-17.855)
+    , value3 = currency(-17.455);
+
+  t.is(value1.value, -17.95, 'currency(-17.955) rounds half up to -17.95');
+  t.is(value2.value, -17.85, 'currency(-17.855) rounds half up to -17.85');
+  t.is(value3.value, -17.45, 'currency(-17.955) rounds half up to -17.45');
+});
+
 test('currency multiplication', t => {
   var value = currency(1.23).multiply(2);
   var floatingValue = currency(.1).multiply(.2);
@@ -95,7 +115,7 @@ test('currency multiplication with precision', t => {
 
 test('currency division', t => {
   var value = currency(9.87).divide(2);
-  t.is(parseFloat(value), 4.93, 'currency(9.87).divide(2) is 4.93');
+  t.is(parseFloat(value), 4.94, 'currency(9.87).divide(2) is 4.94');
 });
 
 test('currency division with precision', t => {