Simplify number rendering and fix -0 in path

Ref #1422

lib/path.js

@@ -241,20 +241,12 @@ exports.parsePathData = parsePathData;
  * @param {StringifyNumberOptions} param
  */
 const stringifyNumber = ({ number, precision }) => {
-  let result;
-  if (precision == null) {
-    result = number.toString();
-  } else {
-    result = number.toFixed(precision);
-    if (result.includes('.')) {
-      result = result.replace(/\.?0+$/, '');
-    }
+  if (precision != null) {
+    const ratio = 10 ** precision;
+    number = Math.round(number * ratio) / ratio;
   }
   // remove zero whole from decimal number
-  if (result !== '0') {
-    result = result.replace(/^0/, '').replace(/^-0/, '-');
-  }
-  return result;
+  return number.toString().replace(/^0\./, '.').replace(/^-0\./, '-.');
 };
 
 /**

lib/path.test.js

@@ -142,26 +142,24 @@ describe('stringify path data', () => {
     ).to.equal('M0-1.2.3 4 5-.6 7 .8');
   });
   it('should configure precision', () => {
+    const pathData = [
+      { command: 'M', args: [0, -1.9876] },
+      { command: 'L', args: [0.3, 3.14159265] },
+      { command: 'L', args: [-0.3, -3.14159265] },
+      { command: 'L', args: [100, 200] },
+    ];
     expect(
       stringifyPathData({
-        pathData: [
-          { command: 'M', args: [0, -1.9876] },
-          { command: 'L', args: [0.3, 3.14159265] },
-          { command: 'L', args: [100, 200] },
-        ],
+        pathData,
         precision: 3,
       })
-    ).to.equal('M0-1.988.3 3.142 100 200');
+    ).to.equal('M0-1.988.3 3.142-.3-3.142 100 200');
     expect(
       stringifyPathData({
-        pathData: [
-          { command: 'M', args: [0, -1.9876] },
-          { command: 'L', args: [0.3, 3.14159265] },
-          { command: 'L', args: [100, 200] },
-        ],
+        pathData,
         precision: 0,
       })
-    ).to.equal('M0-2 0 3 100 200');
+    ).to.equal('M0-2 0 3 0-3 100 200');
   });
   it('allows to avoid spaces after arc flags', () => {
     const pathData = [