fix: Always return matching signed/unsigned zeroes, fixes #72

Author: dcodeIO

index.js

@@ -236,7 +236,7 @@ function fromString(str, unsigned, radix) {
   if (str.length === 0)
     throw Error('empty string');
   if (str === "NaN" || str === "Infinity" || str === "+Infinity" || str === "-Infinity")
-    return ZERO;
+    return unsigned ? UZERO : ZERO;
   if (typeof unsigned === 'number') {
     // For goog.math.long compatibility
     radix = unsigned,
@@ -878,7 +878,7 @@ LongPrototype.sub = LongPrototype.subtract;
  */
 LongPrototype.multiply = function multiply(multiplier) {
   if (this.isZero())
-    return ZERO;
+    return this;
   if (!isLong(multiplier))
     multiplier = fromValue(multiplier);
 
@@ -892,7 +892,7 @@ LongPrototype.multiply = function multiply(multiplier) {
   }
 
   if (multiplier.isZero())
-    return ZERO;
+    return this.unsigned ? UZERO : ZERO;
   if (this.eq(MIN_VALUE))
     return multiplier.isOdd() ? MIN_VALUE : ZERO;
   if (multiplier.eq(MIN_VALUE))