From f79dd29ed34be55fa204b8d135319d3a9a982d7f Mon Sep 17 00:00:00 2001
From: d98762625 <d98762625@gmail.com>
Date: Tue, 15 May 2018 10:47:06 +0100
Subject: [PATCH] port standard deviation ops

---
 src/core/operations/Median.mjs            |  1 +
 src/core/operations/StandardDeviation.mjs | 50 +++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 src/core/operations/StandardDeviation.mjs

diff --git a/src/core/operations/Median.mjs b/src/core/operations/Median.mjs
index 5fdecc8a..51e0e248 100644
--- a/src/core/operations/Median.mjs
+++ b/src/core/operations/Median.mjs
@@ -1,4 +1,5 @@
 /**
+ * @author bwhitn [brian.m.whitney@outlook.com]
  * @author d98762625 [d98762625@gmail.com]
  * @copyright Crown Copyright 2018
  * @license Apache-2.0
diff --git a/src/core/operations/StandardDeviation.mjs b/src/core/operations/StandardDeviation.mjs
new file mode 100644
index 00000000..0357f4e9
--- /dev/null
+++ b/src/core/operations/StandardDeviation.mjs
@@ -0,0 +1,50 @@
+/**
+ * @author bwhitn [brian.m.whitney@outlook.com]
+ * @author d98762625 [d98762625@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+import Operation from "../Operation";
+import Arithmetic from "../lib/Arithmetic";
+import BigNumber from "bignumber.js";
+
+/**
+ * Standard Deviation operation
+ */
+class StandardDeviation extends Operation {
+
+    /**
+     * StandardDeviation constructor
+     */
+    constructor() {
+        super();
+
+        this.name = "Standard Deviation";
+        this.module = "Default";
+        this.description = "Computes the standard deviation of a number list. If an item in the string is not a number it is excluded from the list.<br><br>e.g. <code>0x0a 8 .5</code> becomes <code>4.089281382128433</code>";
+        this.inputType = "string";
+        this.outputType = "BigNumber";
+        this.args = [
+            {
+                "name": "Delimiter",
+                "type": "option",
+                "value": Arithmetic.DELIM_OPTIONS,
+            }
+        ];
+    }
+
+    /**
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {BigNumber}
+     */
+    run(input, args) {
+        const val = Arithmetic._stdDev(Arithmetic._createNumArray(input, args[0]));
+        return val instanceof BigNumber ? val : new BigNumber(NaN);
+
+    }
+
+}
+
+export default StandardDeviation;