Added MessagePack operations

src/core/operations/ToMessagePack.mjs

@@ -0,0 +1,45 @@
+/**
+ * @author Matt C [matt@artemisbot.uk]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import OperationError from "../errors/OperationError.mjs";
+import notepack from "notepack.io";
+
+/**
+ * To MessagePack operation
+ */
+class ToMessagePack extends Operation {
+
+    /**
+     * ToMessagePack constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "To MessagePack";
+        this.module = "Code";
+        this.description = "Converts JSON to MessagePack encoded byte buffer";
+        this.inputType = "JSON";
+        this.outputType = "ArrayBuffer";
+        this.args = [];
+    }
+
+    /**
+     * @param {JSON} input
+     * @param {Object[]} args
+     * @returns {ArrayBuffer}
+     */
+    run(input, args) {
+        try {
+            return notepack.encode(input);
+        } catch (err) {
+            throw new OperationError(`Could not encode JSON to MessagePack: ${err}`);
+        }   
+    }
+
+}
+
+export default ToMessagePack;