Store pending requests

src/actions/sources/loadSourceText.js

@@ -12,6 +12,8 @@ import { isLoaded, isLoading } from "../../utils/source";
 import type { Source } from "../../types";
 import type { ThunkArgs } from "../types";
 
+const loadingSources = {};
+
 async function loadSource(source: Source, { sourceMaps, client }) {
   if (sourceMaps.isOriginalId(source.id)) {
     return await sourceMaps.getOriginalSourceText(source);
@@ -33,16 +35,25 @@ async function loadSource(source: Source, { sourceMaps, client }) {
 export function loadSourceText(source: Source) {
   return async ({ dispatch, getState, client, sourceMaps }: ThunkArgs) => {
     // Fetch the source text only once.
-    if (isLoaded(source) || isLoading(source)) {
+    if (isLoaded(source)) {
       return Promise.resolve(source);
     }
 
+    // Return the pending fetch
+    if (isLoading) {
+      return loadingSources[source.id];
+    }
+
+    loadingSources[source.id] = loadSource(source, { sourceMaps, client });
+
     await dispatch({
       type: "LOAD_SOURCE_TEXT",
       source: source,
-      [PROMISE]: loadSource(source, { sourceMaps, client })
+      [PROMISE]: loadingSources
     });
 
+    delete loadingSources[source.id];
+
     const newSource = getSource(getState(), source.id).toJS();
     if (newSource.isWasm) {
       return;