FIX: fully rely on keyValueStore to prevent error (#12)

* FIX: fully rely on keyValueStore to prevent error

The component was generating errors for some users due to direct access to `localStorage`:

```
TypeError: Cannot convert undefined or null to object
    at Function.keys (<anonymous>)
    at Object.expireOldValues (https://d3bpeqsaub0i6y.cloudfront.net/theme-javascripts/33bf35dc19b970a42f8c1e7d57d8cc72d6205bbd.js?__ws=meta.discourse.org:157:14)
    at Object.initialize (https://d3bpeqsaub0i6y.cloudfront.net/theme-javascripts/33bf35dc19b970a42f8c1e7d57d8cc72d6205bbd.js?__ws=meta.discourse.org:193:12)
    at o.initialize (https://d11a6trkgmumsb.cloudfront.net/assets/discourse-2bd9a9aa6b5c9cbee990a03159f5bff41fe503fe74814c3b66b3770876913dd5.gz.js:68:38)
```

This commits removes old unnecessary code using cookies and uses latest API from core `removeKeys`. Old discourse instances will just not evict old keys which is a minor annoyance.

* linting

javascripts/discourse/initializers/setup.js

@@ -1,7 +1,6 @@
 import showModal from "discourse/lib/show-modal";
 import { withPluginApi } from "discourse/lib/plugin-api";
 import { debounce, later } from "@ember/runloop";
-import cookie, { removeCookie } from "discourse/lib/cookie";
 
 const VALID_TAGS =
   "h1, h2, h3, h4, h5, h6, p, code, blockquote, .md-table, li p";
@@ -66,35 +65,14 @@ function buildSelect(key, placeholder) {
 export default {
   name: "discourse-placeholder-theme-component",
 
-  // TODO: Remove once this change has been live for a few months
-  migrateCookiesToKeyValueStore() {
-    const cookies = document.cookie.split("; ");
-    const oldPlaceholderCookies = [];
-
-    for (let i = 0, l = cookies.length; i < l; i++) {
-      let parts = cookies[i].split("=");
-      if (parts[0].startsWith(STORAGE_PREFIX)) {
-        oldPlaceholderCookies.push(parts[0]);
-      }
-    }
-
-    for (const key of oldPlaceholderCookies) {
-      const value = cookie(key);
-
-      this.setValue(key, value);
-      removeCookie(key);
-    }
-  },
-
   expireOldValues() {
     const now = Date.now();
-    Object.keys(window.localStorage)
+    this.keyValueStore.removeKeys?.((k, v) => {
-      .filter((k) => k.startsWith(STORAGE_PREFIX))
+      if (!k.includes(STORAGE_PREFIX)) {
-      .forEach((k) => {
+        return false;
-        const data = this.keyValueStore.getObject(k);
-        if (!data?.expires || data.expires < now) {
-          this.removeValue(k);
       }
+
+      return !v?.expires || v.expires < now;
     });
   },
 
@@ -123,8 +101,6 @@ export default {
 
   initialize(container) {
     this.keyValueStore = container.lookup("service:key-value-store");
-
-    this.migrateCookiesToKeyValueStore();
     this.expireOldValues();
 
     withPluginApi("0.8.7", (api) => {