diff --git a/.eslintrc.yml b/.eslintrc.yml
index 77b1b72fe68..ebf8048f19c 100644
--- a/.eslintrc.yml
+++ b/.eslintrc.yml
@@ -33,6 +33,15 @@ rules:
     - error
     - max: 1
   promise/catch-or-return: error
+  no-param-reassign:
+    - error
+    - props: true
+      ignorePropertyModificationsFor:
+        - "acc"         # for reduce accumulators
+        - "accumulator" # for reduce accumulators
+        - "el"          # for DOM elements
+        - "element"     # for DOM elements
+        - "state"       # for Vuex mutations
   no-underscore-dangle:
     - error
     - allow:
diff --git a/app/assets/javascripts/diffs/store/mutations.js b/app/assets/javascripts/diffs/store/mutations.js
index 0522e32c410..bc69ae30777 100644
--- a/app/assets/javascripts/diffs/store/mutations.js
+++ b/app/assets/javascripts/diffs/store/mutations.js
@@ -107,7 +107,6 @@ export default {
   },
 
   [types.EXPAND_ALL_FILES](state) {
-    // eslint-disable-next-line no-param-reassign
     state.diffFiles = state.diffFiles.map(file => ({
       ...file,
       collapsed: false,
diff --git a/app/assets/javascripts/fly_out_nav.js b/app/assets/javascripts/fly_out_nav.js
index 8b4f3b05ee7..f820f0dc3f0 100644
--- a/app/assets/javascripts/fly_out_nav.js
+++ b/app/assets/javascripts/fly_out_nav.js
@@ -65,8 +65,8 @@ export const hideMenu = (el) => {
 
   const parentEl = el.parentNode;
 
-  el.style.display = ''; // eslint-disable-line no-param-reassign
-  el.style.transform = ''; // eslint-disable-line no-param-reassign
+  el.style.display = '';
+  el.style.transform = '';
   el.classList.remove(IS_ABOVE_CLASS);
   parentEl.classList.remove(IS_OVER_CLASS);
   parentEl.classList.remove(IS_SHOWING_FLY_OUT_CLASS);
diff --git a/app/assets/javascripts/ide/stores/modules/branches/mutations.js b/app/assets/javascripts/ide/stores/modules/branches/mutations.js
index 081ec2d4c28..0a455f4500f 100644
--- a/app/assets/javascripts/ide/stores/modules/branches/mutations.js
+++ b/app/assets/javascripts/ide/stores/modules/branches/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 
 export default {
diff --git a/app/assets/javascripts/ide/stores/modules/file_templates/mutations.js b/app/assets/javascripts/ide/stores/modules/file_templates/mutations.js
index e413e61eaaa..674782a28ca 100644
--- a/app/assets/javascripts/ide/stores/modules/file_templates/mutations.js
+++ b/app/assets/javascripts/ide/stores/modules/file_templates/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 
 export default {
diff --git a/app/assets/javascripts/ide/stores/modules/merge_requests/mutations.js b/app/assets/javascripts/ide/stores/modules/merge_requests/mutations.js
index 98102a68e08..0eba9c39817 100644
--- a/app/assets/javascripts/ide/stores/modules/merge_requests/mutations.js
+++ b/app/assets/javascripts/ide/stores/modules/merge_requests/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 
 export default {
diff --git a/app/assets/javascripts/ide/stores/modules/pipelines/mutations.js b/app/assets/javascripts/ide/stores/modules/pipelines/mutations.js
index 5a2213bbe89..b4be100cb07 100644
--- a/app/assets/javascripts/ide/stores/modules/pipelines/mutations.js
+++ b/app/assets/javascripts/ide/stores/modules/pipelines/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 import { normalizeJob } from './utils';
 
diff --git a/app/assets/javascripts/ide/stores/mutations.js b/app/assets/javascripts/ide/stores/mutations.js
index 0347f803757..f2bb87ac674 100644
--- a/app/assets/javascripts/ide/stores/mutations.js
+++ b/app/assets/javascripts/ide/stores/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 import projectMutations from './mutations/project';
 import mergeRequestMutation from './mutations/merge_request';
diff --git a/app/assets/javascripts/ide/stores/mutations/file.js b/app/assets/javascripts/ide/stores/mutations/file.js
index a937fb157f8..66f29824898 100644
--- a/app/assets/javascripts/ide/stores/mutations/file.js
+++ b/app/assets/javascripts/ide/stores/mutations/file.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from '../mutation_types';
 import { sortTree } from '../utils';
 import { diffModes } from '../../constants';
diff --git a/app/assets/javascripts/jobs/store/mutations.js b/app/assets/javascripts/jobs/store/mutations.js
index 2a451ef0cd1..cd12ef87d40 100644
--- a/app/assets/javascripts/jobs/store/mutations.js
+++ b/app/assets/javascripts/jobs/store/mutations.js
@@ -1,5 +1,3 @@
-/* eslint-disable no-param-reassign */
-
 import * as types from './mutation_types';
 
 export default {
diff --git a/app/assets/javascripts/pipelines/components/pipelines_table_row.vue b/app/assets/javascripts/pipelines/components/pipelines_table_row.vue
index 29b347824de..a39cc265601 100644
--- a/app/assets/javascripts/pipelines/components/pipelines_table_row.vue
+++ b/app/assets/javascripts/pipelines/components/pipelines_table_row.vue
@@ -132,10 +132,8 @@ export default {
       if (this.pipeline.ref) {
         return Object.keys(this.pipeline.ref).reduce((accumulator, prop) => {
           if (prop === 'path') {
-            // eslint-disable-next-line no-param-reassign
             accumulator.ref_url = this.pipeline.ref[prop];
           } else {
-            // eslint-disable-next-line no-param-reassign
             accumulator[prop] = this.pipeline.ref[prop];
           }
           return accumulator;
diff --git a/app/assets/javascripts/reports/store/mutations.js b/app/assets/javascripts/reports/store/mutations.js
index 1983a8c9e56..b88bff97075 100644
--- a/app/assets/javascripts/reports/store/mutations.js
+++ b/app/assets/javascripts/reports/store/mutations.js
@@ -1,4 +1,3 @@
-/* eslint-disable no-param-reassign */
 import * as types from './mutation_types';
 
 export default {
diff --git a/app/assets/javascripts/vue_shared/vue_resource_interceptor.js b/app/assets/javascripts/vue_shared/vue_resource_interceptor.js
index 73b9131e5ba..b9693892f45 100644
--- a/app/assets/javascripts/vue_shared/vue_resource_interceptor.js
+++ b/app/assets/javascripts/vue_shared/vue_resource_interceptor.js
@@ -28,7 +28,7 @@ Vue.http.interceptors.push((request, next) => {
     response.headers.forEach((value, key) => {
       headers[key] = value;
     });
-
+    // eslint-disable-next-line no-param-reassign
     response.headers = headers;
   });
 });
diff --git a/spec/javascripts/helpers/vue_resource_helper.js b/spec/javascripts/helpers/vue_resource_helper.js
index 70b7ec4e574..0d1bf5e2e80 100644
--- a/spec/javascripts/helpers/vue_resource_helper.js
+++ b/spec/javascripts/helpers/vue_resource_helper.js
@@ -5,6 +5,7 @@ export const headersInterceptor = (request, next) => {
     response.headers.forEach((value, key) => {
       headers[key] = value;
     });
+    // eslint-disable-next-line no-param-reassign
     response.headers = headers;
   });
 };