ECMAScript proposal: Vampire operator

proposal-vampire-operator.md

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+# ECMAScript proposal: Vampire operator
+- [Motivation](#motivation)
+- [High-level API](#high-level-api)
+- [FAQ](#faq)
+
+## Motivation
+
+The vampire operator (',..,') is extremely useful in imperative programming, as it allows to transfer properties from one object to another with mutation as a side effect.
+
+## High-level API
+### Objects
+```js
+const vampire = {};
+const prey = {
+  flag: true,
+  count: 42,
+  items: []
+};
+
+vampire ,.., prey;
+console.log(vampire);
+// {flag: true, count: 42, items: Array(0)}
+console.log(prey);
+// {}
+```
+### Arrays
+```js
+const vampire = [];
+const prey = [42, 'x', NaN];
+
+vampire ,.., prey;
+console.log(vampire);
+// (3) [42, "x", NaN]
+console.log(prey);
+// []
+```
+### FAQ
+#### What are the restrictions on using the vampire operator?
+Use with caution on HolyJs, especially near water.
+#### Should I be wary of a silver bullet?
+No Silver Bullet.
+#### Is there a danger of using the vampire operator on the call stack?
+No, but make sure it's a stack, not a stake.