Added Slack module to fetch user details from Slack

src/server/modules/slack.js

@@ -0,0 +1,41 @@
+const { WebClient: SlackWebClient } = require('@slack/client');
+
+const EMAIL_REGEX = /^(.*)@(.*)$/;
+
+function getAllSlackUsersWithNames(config) {
+    return new Promise((resolve, reject) => {
+        const webClient = new SlackWebClient(config.slack.token);
+
+        webClient.users.list({}, (err, info) => {
+            if (err) {
+                return reject(err);
+            }
+
+            const users = info.members
+                .filter(user => user &&
+                    !user.deleted &&
+                    user.name &&
+                    user.profile &&
+                    user.profile.email &&
+                    user.profile.email.match(EMAIL_REGEX)
+                )
+                .map(user => {
+                    const [, shortName] = user.profile.email.match(EMAIL_REGEX);
+
+                    return {
+                        id: user.id,
+                        name: user.name,
+                        shortName,
+                        email: user.profile.email.toLowerCase()
+                    };
+                });
+
+            return resolve(users);
+        });
+    });
+}
+
+module.exports = {
+    getAllSlackUsersWithNames
+};
+