retrieve custom emoji list via API instead of before page load (#7047)

app/javascript/mastodon/actions/custom_emojis.js

@@ -0,0 +1,37 @@
+import api from '../api';
+
+export const CUSTOM_EMOJIS_FETCH_REQUEST = 'CUSTOM_EMOJIS_FETCH_REQUEST';
+export const CUSTOM_EMOJIS_FETCH_SUCCESS = 'CUSTOM_EMOJIS_FETCH_SUCCESS';
+export const CUSTOM_EMOJIS_FETCH_FAIL = 'CUSTOM_EMOJIS_FETCH_FAIL';
+
+export function fetchCustomEmojis() {
+  return (dispatch, getState) => {
+    dispatch(fetchCustomEmojisRequest());
+
+    api(getState).get('/api/v1/custom_emojis').then(response => {
+      dispatch(fetchCustomEmojisSuccess(response.data));
+    }).catch(error => {
+      dispatch(fetchCustomEmojisFail(error));
+    });
+  };
+};
+
+export function fetchCustomEmojisRequest() {
+  return {
+    type: CUSTOM_EMOJIS_FETCH_REQUEST,
+  };
+};
+
+export function fetchCustomEmojisSuccess(custom_emojis) {
+  return {
+    type: CUSTOM_EMOJIS_FETCH_SUCCESS,
+    custom_emojis,
+  };
+};
+
+export function fetchCustomEmojisFail(error) {
+  return {
+    type: CUSTOM_EMOJIS_FETCH_FAIL,
+    error,
+  };
+};