Added 'Filter XMLLists' code template

Author: tonygermano

Code Templates/Filter XMLLists/LICENSE

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+This Source Code Form is subject to the terms of the Mozilla Public
+License, v. 2.0. If a copy of the MPL was not distributed with this
+file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Files in this subfolder are Copyright Tony Germano 2020.

Code Templates/Filter XMLLists/README.md

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+# Filter XMLLists
+
+The xFilter() method creates a new XMLList with all elements that pass the test implemented by the provided function. This function has some advantages over native e4x filtering.
+- It passes the actual node to be filtered to the filter function rather than operating on it in a *with* context.
+- This allows calling methods on the node as well as referencing child elements that contain javascript operators (most notibly the . character, which is heavily used in hl7.)
+- Additional parameters let you limit the number of results returned or throw exceptions if there is an unexpected number of filtered results.
+
+## Syntax
+
+```javascript
+var filteredList = xFilter(xmlList, callback(node[, index[, list]])[, minLimit[, maxReturned[, enforceMax]]])
+```
+
+### Parameters:
+
+- **xmlList** The XMLList to be filtered
+- **callback** Function is a predicate, to test each node of the XMLList. Return `true` to keep the element, `false` otherwise. It accepts 3 arguments
+  - **node** The current node being processed in the XMLList
+  - **index** The index of the current node being processed in the XMLList
+  - **list** The XMLList passed as the first parameter of xFilter()
+- **minLimit** Optional. Throw a RangeError if the length of the xmlList to be returned is fewer than this number. Defaults to no lower limit.
+- **maxReturned** Optional. Only return up to this many results. This can be used to short circuit the function if you do not need all of the results. Defaults to no upper limit.
+- **enforceMax** Optional. Throw a RangeError if more than maxReturned results will be returned. Defaults to false.
+
+### Return Value
+
+A new XMLList with the nodes that pass the test (up to maxReturned.) If no nodes pass the test and minLimit is not set, an empty XMLList will be returned.
+
+
+### Examples
+Get the id that represents the NPI number from the repetition of OBR-16 where OBR-16.9 equals `NPI` or empty string if it doesn't exist. Stop looking after the first match if more than one repetition qualifies.
+
+```javascript
+var npiOrdering = xFilter(msg.OBR['OBR.16'], function(obr16) {return obr16['OBR.16.9']=='NPI'}, 0, 1);
+var npiNumber = npiOrdering['OBR.16.1'].toString();
+```
+
+Compile the OBX-5 text of all OBX segments ignoring the first 5 OBX segments and any OBX segment where OBX-3.2 is not `Report`. Ensure at least one line is printed. Arrow functions can be used when ES6 mode is enabled.
+
+```javascript
+var clippedReport = new java.lang.StringBuilder();
+try {
+    for each (var obx in xFilter(msg.OBX, (obx,i) => (i>4 && obx['OBX.3']['OBX.3.2']=='Report'), 1)) {
+        clippedReport.append(obx['OBX.5']['OBX.5.1']).append('\n');
+    }
+}
+// let other exceptions go unchecked
+catch(e if e instanceof RangeError) {
+    // handle report that does not meet requirements
+}
+```
+
+

Code Templates/Filter XMLLists/xFilter.js

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+/**
+	Improved XMLList filter over built-in e4x filters.
+
+        @copyright 2020 Tony Germano
+        @license MPL-2.0
+
+	@param {XMLList} xmlList - The XMLList to be filtered
+	@param {Function} callback - Function is a predicate, to test each node of the XMLList. Return
+		true to keep the element, false otherwise. It accepts 3 arguments - the node, the index of the node,
+		and xmlList as passed into xFilter
+	@param {Number} minLimit - (Optional) throw RangeError if at least this many nodes do not pass the
+		filter
+	@param {Number} maxReturned - (Optional) only return up to this many results
+	@param {Boolean} enforceMax - (Optional) throw RangeError if more than maxReturned results will
+		be returned
+	@return {XMLList} new XMLList containing filtered results
+*/
+function xFilter(xmlList, callback, minLimit, maxReturned, enforceMax) {
+    var ret = new XMLList();
+    for (var i = 0; i < xmlList.length(); i++) {
+        var node = xmlList[i];
+        if (callback(node, i, xmlList)) {
+            ret += node;
+            if (enforceMax) {
+                if (ret.length() > maxReturned) {
+                    throw new RangeError('The number of filtered results is more than ' + maxReturned);
+                }
+            }
+            else if (ret.length() == maxReturned) {
+                break;
+            }
+        }
+    }
+    if (ret.length() < minLimit) {
+        throw new RangeError('The number of filtered results is less than ' + minLimit);
+    }
+    return ret;
+}

README.md

@@ -12,6 +12,7 @@ This is a repository of example channels, code templates, and other scripts you
  - Encrypt PDF
  - Execute Runtime Command
  - Extract Text From PDF
+ - Filter XMLLists
  - Fix HL7 Node Order
  - Get Num Pages In PDF
  - Get Segments After a Particular Segment