fix: convert value to String if toString method exist

Author: cdoublev

lib/CSSStyleDeclaration.test.js

@@ -352,6 +352,38 @@ describe('CSSStyleDeclaration', () => {
     expect(style.fillOpacity).toEqual('0');
   });
 
+  test('setting a value to empty string or null should remove the value', () => {
+    var style = new CSSStyleDeclaration();
+    style.setProperty('opacity', 0);
+    expect(style.opacity).toEqual('0');
+    style.setProperty('opacity', null);
+    expect(style.opacity).toEqual('');
+    style.setProperty('opacity', 0);
+    expect(style.opacity).toEqual('0');
+    style.setProperty('opacity', '');
+    expect(style.opacity).toEqual('');
+  });
+
+  test('setting a value to an object implementing toString() should work', () => {
+    var style = new CSSStyleDeclaration();
+    var object = {
+      toString: function() {
+        return 1;
+      },
+    };
+    style.setProperty('opacity', object);
+    expect(style.opacity).toEqual('1');
+    style.setProperty('opacity', [0]);
+    expect(style.opacity).toEqual('0');
+    object = {
+      toString: function() {
+        return [1]; // Not recursive: [1].toString() === '1'
+      },
+    };
+    style.setProperty('opacity', object);
+    expect(style.opacity).toEqual('0');
+  });
+
   test('onchange callback should be called when the csstext changes', () => {
     var style = new CSSStyleDeclaration(function(cssText) {
       expect(cssText).toEqual('opacity: 0;');

lib/parsers.js

@@ -40,6 +40,9 @@ exports.valueType = function valueType(val) {
   if (val === '' || val === null) {
     return exports.TYPES.NULL_OR_EMPTY_STR;
   }
+  if (typeof val.toString === 'function') {
+    val = val.toString();
+  }
   if (typeof val === 'number') {
     val = val.toString();
   }