4 files changed, 8 insertions, 3 deletions
diff --git a/.eslintrc.js b/.eslintrc.js
index 7dda01108..2a882f59c 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -79,6 +79,11 @@ module.exports = {
     'no-irregular-whitespace': 'error',
     'no-mixed-spaces-and-tabs': 'warn',
     'no-nested-ternary': 'warn',
+    'no-restricted-properties': [
+      'error',
+      { property: 'substring', message: 'Use .slice instead of .substring.' },
+      { property: 'substr', message: 'Use .slice instead of .substr.' },
+    ],
     'no-trailing-spaces': 'warn',
     'no-undef': 'error',
     'no-unreachable': 'error',
diff --git a/app/javascript/mastodon/features/emoji/emoji_mart_search_light.js b/app/javascript/mastodon/features/emoji/emoji_mart_search_light.js
index e4519a13e..70694ab6d 100644
--- a/app/javascript/mastodon/features/emoji/emoji_mart_search_light.js
+++ b/app/javascript/mastodon/features/emoji/emoji_mart_search_light.js
@@ -124,7 +124,7 @@ function search(value, { emojisToShowFilter, maxResults, include, exclude, custo
           for (let id in aPool) {
             let emoji = aPool[id],
               { search } = emoji,
-              sub = value.substr(0, length),
+              sub = value.slice(0, length),
               subIndex = search.indexOf(sub);
 
             if (subIndex !== -1) {
diff --git a/app/javascript/mastodon/features/status/components/card.js b/app/javascript/mastodon/features/status/components/card.js
index 90f9ae7ae..3d81bcb29 100644
--- a/app/javascript/mastodon/features/status/components/card.js
+++ b/app/javascript/mastodon/features/status/components/card.js
@@ -32,7 +32,7 @@ const trim = (text, len) => {
     return text;
   }
 
-  return text.substring(0, cut) + (text.length > len ? '…' : '');
+  return text.slice(0, cut) + (text.length > len ? '…' : '');
 };
 
 const domParser = new DOMParser();
diff --git a/app/javascript/mastodon/features/video/index.js b/app/javascript/mastodon/features/video/index.js
index 8d47e479a..4f90e955f 100644
--- a/app/javascript/mastodon/features/video/index.js
+++ b/app/javascript/mastodon/features/video/index.js
@@ -91,7 +91,7 @@ export const fileNameFromURL = str => {
   const pathname = url.pathname;
   const index    = pathname.lastIndexOf('/');
 
-  return pathname.substring(index + 1);
+  return pathname.slice(index + 1);
 };
 
 export default @injectIntl