fix(NumberPicker): float bug by chrome. Close #79

Author: 潕量

src/number-picker/index.jsx

@@ -304,6 +304,8 @@ class NumberPicker extends React.Component {
         let result;
         if (typeof val === 'number') {
             result = (precisionFactor * val + precisionFactor * step) / precisionFactor;
+
+            result = this.hackChrome(result);
         } else {
             result = min === -Infinity ? step : min;
         }
@@ -317,17 +319,27 @@ class NumberPicker extends React.Component {
         if (typeof val === 'number') {
             result = (precisionFactor * val - precisionFactor * step) / precisionFactor;
 
-            // in chrome browser: 0.3 - 0.2 = 0.09999999999, we should creact to 0.1
-            const precision = this.getPrecision();
-            if (precision > 0) {
-                result = Number(Number(result).toFixed(precision));
-            }
+            result = this.hackChrome(result);
         } else {
             result = min === -Infinity ? -step : min;
         }
         return result;
     }
 
+    /**
+     * fix bug in chrome browser
+     * 0.28 + 0.01 = 0.29000000000000004
+     * 0.29 - 0.01 = 0.27999999999999997
+     * @param {Number} value value
+     */
+    hackChrome(value) {
+        const precision = this.getPrecision();
+        if (precision > 0) {
+            return Number(Number(value).toFixed(precision));
+        }
+        return value;
+    }
+
     step(type, e) {
         if (e) {
             e.preventDefault();

test/number-picker/index-spec.js

@@ -318,4 +318,24 @@ describe('number-picker', () => {
             done();
         });
     });
+    describe('chrome bug hack', () => {
+        it('0.28 + 0.01 should be 0.29 not 0.29000000000000004', (done) => {
+            let onChange = (value) => {
+                    assert(value === 0.29);
+                    done();
+                },
+                wrapper = mount(<NumberPicker defaultValue={0.28} onChange={onChange} step={0.01} precision={2}/>);
+
+            wrapper.find('button').at(0).simulate('click');
+        });
+        it('0.29 - 0.01 should be 0.28 not 0.27999999999999997', (done) => {
+            let onChange = (value) => {
+                    assert(value === 0.28);
+                    done();
+                },
+                wrapper = mount(<NumberPicker defaultValue={0.29} onChange={onChange} step={0.01} precision={2}/>);
+
+            wrapper.find('button').at(1).simulate('click');
+        });
+    });
 });