diff --git a/app/javascript/src/components/Navigation/components/ActivityElement.jsx b/app/javascript/src/components/Navigation/components/ActivityElement.jsx
index e46d924c7..c3e539a65 100644
--- a/app/javascript/src/components/Navigation/components/ActivityElement.jsx
+++ b/app/javascript/src/components/Navigation/components/ActivityElement.jsx
@@ -1,6 +1,7 @@
 // @flow
 
 import React from "react";
+import type { Node } from "react";
 import { FormattedDate } from "react-intl";
 import { Tooltip, OverlayTrigger } from "react-bootstrap";
 import styled from "styled-components";
@@ -14,6 +15,10 @@ import {
 
 import { NAME_TRUNCATION_LENGTH } from "../../../config/constants/numeric";
 
+type InputActivity = {
+  activity: Activity
+}
+
 const StyledLi = styled.li`
   border-radius: 0.25em;
   margin-bottom: 1em;
@@ -37,42 +42,42 @@ const TextSpan = styled.span`
   display: table-cell;
   padding: 3px 10px;
   text-align: justify;
-`
+`;
 
-function truncatedTooltip(id, text) {
+function truncatedTooltip(id: string, text: any): Node {
   return (
-    <OverlayTrigger overlay={(
-      <Tooltip id={id}>
-        {text}
-      </Tooltip>
-    )} placement="bottom">
-        <span>
-          {text.substring(0, NAME_TRUNCATION_LENGTH)}...
-        </span>
+    <OverlayTrigger
+      overlay={<Tooltip id={id}>{text}</Tooltip>}
+      placement="bottom"
+    >
+      <span>{text.substring(0, NAME_TRUNCATION_LENGTH)}...</span>
     </OverlayTrigger>
   );
 }
 
-function taskPath(activity) {
+function taskPath(activity: Activity): Node {
   return (
-    <span>&nbsp;
-      [&nbsp;<FormattedMessage id="general.project" />:&nbsp;
+    <span>
+      &nbsp; [&nbsp;<FormattedMessage id="general.project" />:&nbsp;
       {activity.project.length > NAME_TRUNCATION_LENGTH ? (
-        truncatedTooltip('activity_modal.long_project_tooltip', activity.project)
-      ):(
+        truncatedTooltip(
+          "activity_modal.long_project_tooltip",
+          activity.project
+        )
+      ) : (
         <span>{activity.project}</span>
       )},&nbsp;
       <FormattedMessage id="general.task" />:&nbsp;
       {activity.task.length > NAME_TRUNCATION_LENGTH ? (
-        truncatedTooltip('activity_modal.long_task_tooltip', activity.task)
-      ):(
+        truncatedTooltip("activity_modal.long_task_tooltip", activity.task)
+      ) : (
         <span>{activity.task}</span>
       )}&nbsp;]
     </span>
   );
 }
 
-const ActivityElement = ({ activity }: Activity ): Node => (
+const ActivityElement = ({ activity }: InputActivity ): Node => (
   <StyledLi>
     <TimeSpan>
       <FormattedDate
@@ -87,6 +92,7 @@ const ActivityElement = ({ activity }: Activity ): Node => (
       <span dangerouslySetInnerHTML={{ __html: activity.message }} />
       {activity.task && taskPath(activity)}
     </TextSpan>
-  </StyledLi>;
+  </StyledLi>
+);
 
 export default ActivityElement;
diff --git a/app/javascript/src/components/Navigation/components/GlobalActivitiesModal.jsx b/app/javascript/src/components/Navigation/components/GlobalActivitiesModal.jsx
index 999d863de..095cde7a0 100644
--- a/app/javascript/src/components/Navigation/components/GlobalActivitiesModal.jsx
+++ b/app/javascript/src/components/Navigation/components/GlobalActivitiesModal.jsx
@@ -1,7 +1,7 @@
 // @flow
 
 import React, { Component } from "react";
-import type { Element } from "react";
+import type { Element, Node } from "react";
 import { FormattedMessage } from "react-intl";
 import { Button, Modal } from "react-bootstrap";
 import _ from "lodash";
@@ -62,7 +62,7 @@ class GlobalActivitiesModal extends Component<Props, State> {
     key: number,
     activity: Activity,
     date: Date
-  ) {
+  ): Node {
     return [
       <ActivityDateElement key={date} date={date} />,
       <ActivityElement key={key} activity={activity} />
@@ -95,35 +95,37 @@ class GlobalActivitiesModal extends Component<Props, State> {
   }
 
   mapActivities(): Array<*> {
-    return this.state.activities.map((activity, i, arr) => {
-      // when the backend bug will be fixed
-      const newDate = new Date(activity.createdAt);
-      // returns a label with "today" if the date of the activity is today
-      if (i === 0 && newDate.toDateString() === new Date().toDateString()) {
-        return GlobalActivitiesModal.renderActivityDateElement(
-          i,
-          activity,
-          newDate
-        );
+    return this.state.activities.map(
+      (activity: Activity, i: number, arr: Array<*>) => {
+        // when the backend bug will be fixed
+        const newDate = new Date(activity.createdAt);
+        // returns a label with "today" if the date of the activity is today
+        if (i === 0 && newDate.toDateString() === new Date().toDateString()) {
+          return GlobalActivitiesModal.renderActivityDateElement(
+            i,
+            activity,
+            newDate
+          );
+        }
+        // else checks if the previous activity is newer than current
+        // and displays a label with the date
+        const prevDate =
+          i !== 0 ? new Date(arr[i - 1].createdAt) : new Date(1901, 1, 1);
+        // filter only date from createdAt without minutes and seconds
+        // used to compare dates
+        const parsePrevDate = new Date(prevDate.toDateString());
+        const parseNewDate = new Date(newDate.toDateString());
+        if (parsePrevDate.getTime() > parseNewDate.getTime()) {
+          return GlobalActivitiesModal.renderActivityDateElement(
+            i,
+            activity,
+            newDate
+          );
+        }
+        // returns the default activity element
+        return <ActivityElement key={activity.id} activity={activity} />;
       }
-      // else checks if the previous activity is newer than current
-      // and displays a label with the date
-      const prevDate =
-        i !== 0 ? new Date(arr[i - 1].createdAt) : new Date(1901, 1, 1);
-      // filter only date from createdAt without minutes and seconds
-      // used to compare dates
-      const parsePrevDate = new Date(prevDate.toDateString());
-      const parseNewDate = new Date(newDate.toDateString());
-      if (parsePrevDate.getTime() > parseNewDate.getTime()) {
-        return GlobalActivitiesModal.renderActivityDateElement(
-          i,
-          activity,
-          newDate
-        );
-      }
-      // returns the default activity element
-      return <ActivityElement key={activity.id} activity={activity} />;
-    });
+    );
   }
 
   displayActivities() {
diff --git a/flow-typed/types.js b/flow-typed/types.js
index 2492b8196..a81fd977e 100644
--- a/flow-typed/types.js
+++ b/flow-typed/types.js
@@ -35,8 +35,8 @@ export type Activity = {
   message: string,
   createdAt: string,
   timezone: string,
-  project?: string,
-  task?: string
+  project: string,
+  task: string
 };
 
 export type Notification = {