Task: Weekly Coffee Chat (Mattermost Version)

n8n workflow:
{"id":"7","name":"Coffee Bot (Mattermost)","nodes":[{"name":"Divide into groups","type":"n8n-nodes-base.function","position":[1060,300],"parameters":{"functionCode":"const ideal_group_size = 3;\nlet groups = [];\nlet data_as_array = [];\nlet newItems = [];\n\n// Take all the users and add them to an array\nfor (let j = 0; j < items.length; j++) {\n  data_as_array.push({username: items[j].json.username, email: items[j].json.email});\n}\n\n// Fisher-Yates (aka Knuth) Shuffle\nfunction shuffle(array) {\n  var currentIndex = array.length, temporaryValue, randomIndex;\n\n  // While there remain elements to shuffle...\n  while (0 !== currentIndex) {\n\n    // Pick a remaining element...\n    randomIndex = Math.floor(Math.random() * currentIndex);\n    currentIndex -= 1;\n\n    // And swap it with the current element.\n    temporaryValue = array[currentIndex];\n    array[currentIndex] = array[randomIndex];\n    array[randomIndex] = temporaryValue;\n  }\n\n  return array;\n}\n\n// Randomize the sequence of names in the array\ndata_as_array = shuffle(data_as_array);\n\n// Create groups of ideal group size (3)\nfor (let i = 0; i < data_as_array.length; i += ideal_group_size) {\n  groups.push(data_as_array.slice(i, i + ideal_group_size));\n}\n\n// Make sure that no group has just one person. If it does, take\n// one from previous group and add it to that group \nfor (let k = 0; k < groups.length; k++) {\n  if (groups[k].length === 1) {\n    groups[k].push(groups[k-1].shift());\n  }\n}\n\nfor (let l = 0; l < groups.length; l++) {\n    newItems.push({json: {groupsUsername: groups[l].map(a=> a.username), groupsEmail: groups[l].map(b=> b.email)}})\n}\n\nreturn newItems;"},"typeVersion":1},{"name":"Greetings","type":"n8n-nodes-base.mattermost","position":[650,300],"parameters":{"message":"👋 Happy Monday\n\nGroups for this week's virtual coffee are:","channelId":"Enter Your Channel ID","attachments":[],"otherOptions":{}},"credentials":{"mattermostApi":"Mattermost Cred"},"typeVersion":1},{"name":"Weekly trigger on monday","type":"n8n-nodes-base.cron","position":[450,300],"parameters":{"triggerTimes":{"item":[{"hour":10,"mode":"everyWeek"}]}},"typeVersion":1},{"name":"Announce groups","type":"n8n-nodes-base.mattermost","position":[1250,200],"parameters":{"message":"=☀️ {{$node[\"Divide into groups\"].json[\"groupsUsername\"].join(', ')}}","channelId":"=","attachments":[],"otherOptions":{}},"credentials":{"mattermostApi":"Mattermost Cred"},"typeVersion":1},{"name":"Employees in coffee chat channel","type":"n8n-nodes-base.mattermost","position":[850,300],"parameters":{"resource":"user","operation":"getAll","additionalFields":{"inChannel":"={{$node[\"Greetings\"].parameter[\"channelId\"]}}"}},"credentials":{"mattermostApi":"Mattermost Cred"},"typeVersion":1},{"name":"Send calendar invites","type":"n8n-nodes-base.googleCalendar","position":[1250,400],"parameters":{"end":"2020-12-17T18:38:49.000Z","start":"2020-12-17T18:08:49.000Z","calendar":"Enter Your Google Calendar","additionalFields":{"summary":"n8n coffee catchup","attendees":["={{$node[\"Divide into groups\"].json[\"groupsEmail\"].join(',')}}"],"guestsCanModify":true,"conferenceDataUi":{"conferenceDataValues":{"conferenceSolution":"hangoutsMeet"}}}},"credentials":{"googleCalendarOAuth2Api":"Google Calendar Cred"},"typeVersion":1}],"active":false,"settings":{},"connections":{"Greetings":{"main":[[{"node":"Employees in coffee chat channel","type":"main","index":0}]]},"Divide into groups":{"main":[[{"node":"Announce groups","type":"main","index":0},{"node":"Send calendar invites","type":"main","index":0}]]},"Weekly trigger on monday":{"main":[[{"node":"Greetings","type":"main","index":0}]]},"Employees in coffee chat channel":{"main":[[{"node":"Divide into groups","type":"main","index":0}]]}}}