Handle QuotaExceededError in StyleStore (#1253)

## Launch Checklist

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checklist. -->

When localStorage is full you start getting a "QuotaExceededError".
RIght now Maputnik does not handle this situation gracefully, it just
fails loading the style with a non-descriptive error message.

This PR purges localStorage and tries again when this particular error
happens.

It still does not show a descriptive error message. If you try to load a
style that is larger than what localStorage can handle, it will still
fail with a non-descriptive error message.

Increased the size of `example-style.json` so that it causes a
QuotaExceededError when running the regression test (try it before and
after this PR).


 - [x] Briefly describe the changes in this PR.
 - [x] Link to related issues. N/A
- [x] Include before/after visuals or gifs if this PR includes visual
changes. N/A
 - [x] Write tests for all new functionality.
 - [x] Add an entry to `CHANGELOG.md` under the `## main` section.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

cypress/e2e/maputnik-driver.ts

@@ -8,8 +8,10 @@ const baseUrl = "http://localhost:8888/";
 
 const styleFromWindow = (win: Window) => {
   const styleId = win.localStorage.getItem("maputnik:latest_style");
-  const styleItem = win.localStorage.getItem(`maputnik:style:${styleId}`);
-  const obj = JSON.parse(styleItem || "");
+  const styleItemKey = `maputnik:style:${styleId}`;
+  const styleItem = win.localStorage.getItem(styleItemKey);
+  if (!styleItem) throw new Error("Could not get styleItem from localStorage");
+  const obj = JSON.parse(styleItem);
   return obj;
 };
 

cypress/e2e/modals.cy.ts

@@ -275,4 +275,44 @@ describe("modals", () => {
   describe("sources", () => {
     it("toggle");
   });
+
+  describe("Handle localStorage QuotaExceededError", () => {
+    it("handles quota exceeded error when opening style from URL", () => {
+      // Clear localStorage to start fresh
+      cy.clearLocalStorage();
+
+      // fill localStorage until we get a QuotaExceededError
+      cy.window().then(win => {
+        let chunkSize = 1000;
+        const chunk = new Array(chunkSize).join("x");
+        let index = 0;
+
+        // Keep adding until we hit the quota
+        while (true) {
+          try {
+            const key = `maputnik:fill-${index++}`;
+            win.localStorage.setItem(key, chunk);
+          } catch (e: any) {
+            // Verify it's a quota error
+            if (e.name === 'QuotaExceededError') {
+              if (chunkSize <= 1) return;
+              else {
+                chunkSize /= 2;
+                continue;
+              }
+            }
+            throw e; // Unexpected error
+          }
+        }
+      });
+
+      // Open the style via URL input
+      when.click("nav:open");
+      when.setValue("modal:open.url.input", get.exampleFileUrl());
+      when.click("modal:open.url.button");
+
+      then(get.responseBody("example-style.json")).shouldEqualToStoredStyle();
+      then(get.styleFromLocalStorage()).shouldExist();
+    });
+  });
 });