Add support for binary and octal literals in strings to the Number …

…constructor. Fixes #358.
paulmillr · Aug 15, 2015 · 73598be · 73598be
1 parent 95ccec5
commit 73598be
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diff --git a/es6-shim.js b/es6-shim.js
@@ -1132,6 +1132,49 @@
     }, true);
   }
 
+  if (Number('0o10') !== 8 || Number('0b10') !== 2) {
+    var OrigNumber = Number;
+    var isBinary = Function.bind.call(Function.call, RegExp.prototype.test, /^0b/i);
+    var isOctal = Function.bind.call(Function.call, RegExp.prototype.test, /^0o/i);
+    var toPrimitive = function (O) { // need to replace this with `es-to-primitive/es6`
+      var result;
+      if (typeof O.valueOf === 'function') {
+        result = O.valueOf();
+        if (Type.primitive(result)) {
+          return result;
+        }
+      }
+      if (typeof O.toString === 'function') {
+        result = O.toString();
+        if (Type.primitive(result)) {
+          return result;
+        }
+      }
+      throw new TypeError('No default value');
+    };
+    var NumberShim = function Number(value) {
+      var primValue = Type.primitive(value) ? value : toPrimitive(value, 'number');
+      if (typeof primValue === 'string') {
+        if (isBinary(primValue)) {
+          primValue = parseInt(_strSlice(primValue, 2), 2);
+        } else if (isOctal(primValue)) {
+          primValue = parseInt(_strSlice(primValue, 2), 8);
+        }
+      }
+      if (this instanceof Number) {
+        return new OrigNumber(primValue);
+      }
+      /* jshint newcap: false */
+      return OrigNumber(primValue);
+      /* jshint newcap: true */
+    };
+    wrapConstructor(OrigNumber, NumberShim, {});
+    /*globals Number: true */
+    Number = NumberShim;
+    Value.redefine(globals, 'Number', NumberShim);
+    /*globals Number: false */
+  }
+
   var maxSafeInteger = Math.pow(2, 53) - 1;
   defineProperties(Number, {
     MAX_SAFE_INTEGER: maxSafeInteger,

diff --git a/test/number.js b/test/number.js
@@ -354,5 +354,19 @@ describe('Number', function () {
       expect(+a).to.equal(0xA);
       expect(a instanceof Number).to.equal(true);
     });
+
+    it('works with binary literals in string form', function () {
+      expect(Number('0b1')).to.equal(1);
+      expect(Number('0b10')).to.equal(2);
+      expect(Number('0b11')).to.equal(3);
+      expect(Number({ toString: function () { return '0b100'; }, valueOf: function () { return '0b101'; } })).to.equal(5);
+    });
+
+    it('works with octal literals in string form', function () {
+      expect(Number('0o7')).to.equal(7);
+      expect(Number('0o10')).to.equal(8);
+      expect(Number('0o11')).to.equal(9);
+      expect(Number({ toString: function () { return '0o12'; }, valueOf: function () { return '0o13'; } })).to.equal(11);
+    });
   });
 });