Remove element from listfield (ServiceNowDevProgram#715)

* Create removeFromList.js

Code to remove element from a list field

* Create readme.md

Add some documentation about the code, usage and community reference.

Author: Lacah

Background Scripts/Remove element from list field/readme.md

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+This script can be used to remove a specific element from a list field across multiple records in a table that match a query condition.
+
+It requires 3 variables to be set:
+- table {string}: the name of the table to run on, e.g. 'kb_knowledge_block'
+- listField {string}: the name of the list field on the above table to remove an element from, e.g. 'can_read_user_criteria'
+- whatToRemove {sysId}: the sys_id of the element to remove from the list field, e.g. sys_id of a specific user critria
+
+The script contains additional inline comments about what it does while runnning.
+
+Further context annd use case can be read in the [related community post](https://www.servicenow.com/community/developer-forum/glide-list-type-field-need-to-remove-one-value-in-bulk/m-p/2431257#M947276) where this code was used as the solution by yours truly.

Background Scripts/Remove element from list field/removeFromList.js

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+var table = ''; // Name of the table, e.g. kb_knowledge_block
+var listField = ''; // Name of the list field to remove an element from, e.g. can_read_user_criteria
+var whatToRemove = ''; // Sys_id of the element to remove from the list field, e.g. sys_id of user criteria
+var encQ = listField + 'LIKE' + whatToRemove; // encoded query to limit queried record to those that contain the element we want to remove
+var listArray = []; // initial array variable declaration
+var elementIndex = -1; // initial index variable declaration
+
+
+/* Run a GlideRecord query to find all records that contain the element to be deleted from the specifid list field */
+var listGr = new GlideRecord(table);
+listGr.addEncodedQuery(encQ);
+listGr.query();
+while(listGr.next()) {
+  listArray = listGr[listField].toString().split(','); // set the array variable based on the List field of the found record
+  elementIndex = listArray.indexOf(whatToRemove); // search for the element to remove from this particular record
+  /* Only try to remove the element and update the record if it was found, i.e. not -1 */
+  if(elementIndex > -1) {
+    listArray.splice(elementIndex,1);
+    listGr.setValue(listField,listArray);
+    listGr.update();
+  }
+  /* Reset the initial array related variables */
+  listArray = [];
+  elementIndex = -1;
+}