function to copy objects

README.md

@@ -11,4 +11,10 @@ util.truncate_decimal(12.345678, 2);
 
 // will return null instead of throwing on invalid json
 util.try_parse_json('{{foo');
+
+// copy an object to prevent modification of the original
+const obj = {foo:'bar'};
+const copy = util.copy_object(obj);
+copy.foo = 'baz';
+console.log(obj.foo); // bar
 ```

index.js

@@ -32,7 +32,19 @@ function try_parse_json (text) {
   return null;
 }
 
+
+/**
+ * copy an object to prevent modification to the original
+ *
+ * @param {object} obj object to copy
+ * @returns {object} copy
+ */
+function copy_object (obj) {
+  return JSON.parse (JSON.stringify (obj));
+}
+
 module.exports = {
   truncate_decimal,
-  try_parse_json
+  try_parse_json,
+  copy_object
 };

test/index.js

@@ -30,3 +30,11 @@ test ('try_parse_json should fail', (t) => {
     t.is (json, null);
   });
 });
+
+test ('copy object', (t) => {
+  const obj = {foo:'bar'};
+  const copy = util.copy_object(obj);
+  copy.foo = 'baz';
+  t.is(copy.foo, 'baz');
+  t.is(obj.foo, 'bar');
+});