Used bignumber.js for add and minus

Author: glim-palo

src/evaluate-by-operator/operator/add.js

@@ -1,16 +1,23 @@
 import {toNumber} from './../../helper/number';
 import {ERROR_VALUE} from './../../error';
+import BigNumber from 'bignumber.js';
 
 export const SYMBOL = '+';
 
 export default function func(first, ...rest) {
-  const result = rest.reduce((acc, value) => acc + toNumber(value), toNumber(first));
+  try {
+    const result = rest.reduce((acc, value) => {
+      return (new BigNumber(acc)).plus(new BigNumber(value)).toNumber();
+    }, first);
 
-  if (isNaN(result)) {
+    if (isNaN(result)) {
+      throw Error(ERROR_VALUE);
+    }
+
+    return result;
+  } catch (error) {
     throw Error(ERROR_VALUE);
   }
-
-  return result;
 };
 
 func.SYMBOL = SYMBOL;

src/evaluate-by-operator/operator/minus.js

@@ -1,16 +1,23 @@
 import {toNumber} from './../../helper/number';
 import {ERROR_VALUE} from './../../error';
+import BigNumber from 'bignumber.js';
 
 export const SYMBOL = '-';
 
 export default function func(first, ...rest) {
-  const result = rest.reduce((acc, value) => acc - toNumber(value), toNumber(first));
+  try {
+    const result = rest.reduce((acc, value) => {
+      return (new BigNumber(acc)).minus(new BigNumber(value)).toNumber();
+    }, first);
 
-  if (isNaN(result)) {
+    if (isNaN(result)) {
+      throw Error(ERROR_VALUE);
+    }
+
+    return result;
+  } catch (error) {
     throw Error(ERROR_VALUE);
   }
-
-  return result;
 };
 
 func.SYMBOL = SYMBOL;

test/unit/evaluate-by-operator/operator/add.js

@@ -9,7 +9,7 @@ describe('add operator', () => {
     expect(func(2, 8.8)).to.eq(10.8);
     expect(func('2', 8.8)).to.eq(10.8);
     expect(func('2', '8.8')).to.eq(10.8);
-    expect(func('2', '-8.8', 6, 0.4)).to.eq(-0.4000000000000007);
+    expect(func('2', '-8.8', 6, 0.4)).to.eq(-0.4);
     expect(() => func('foo', ' ', 'bar', ' baz')).to.throw('VALUE');
     expect(() => func('foo', 2)).to.throw('VALUE');
   });

test/unit/evaluate-by-operator/operator/minus.js

@@ -6,9 +6,9 @@ describe('minus operator', () => {
   });
 
   it('should correctly process values', () => {
-    expect(func(2, 8.8)).to.eq(-6.800000000000001);
-    expect(func('2', 8.8)).to.eq(-6.800000000000001);
-    expect(func('2', '8.8')).to.eq(-6.800000000000001);
+    expect(func(2, 8.8)).to.eq(-6.8);
+    expect(func('2', 8.8)).to.eq(-6.8);
+    expect(func('2', '8.8')).to.eq(-6.8);
     expect(func('2', '-8.8', 6, 0.4)).to.eq(4.4);
     expect(() => func('foo', ' ', 'bar', ' baz')).to.throw('VALUE');
     expect(() => func('foo', 2)).to.throw('VALUE');