Opt for url regex matching over try catch

Author: spalmurray

public/manifest.firefox.json

@@ -16,12 +16,8 @@
 
   "content_scripts": [
     {
-      "matches": ["*://github.com/*/*/blob/*"],
-      "js": ["js/vendor.js", "js/githubFile.js"]
-    },
-    {
-      "matches": ["*://github.com/*/*/pull/*/files*"],
-      "js": ["js/vendor.js", "js/githubPR.js"]
+      "matches": ["*://github.com/*"],
+      "js": ["js/vendor.js", "js/githubFile.js", "js/githubPR.js"]
     }
   ],
 

public/manifest.json

@@ -16,12 +16,8 @@
 
   "content_scripts": [
     {
-      "matches": ["*://github.com/*/*/blob/*"],
-      "js": ["js/vendor.js", "js/githubFile.js"]
-    },
-    {
-      "matches": ["*://github.com/*/*/pull/*/files*"],
-      "js": ["js/vendor.js", "js/githubPR.js"]
+      "matches": ["*://github.com/*"],
+      "js": ["js/vendor.js", "js/githubFile.js", "js/githubPR.js"]
     }
   ],
 

src/content/github/common/utils.ts

@@ -0,0 +1,12 @@
+// Note that we're guaranteed to be on a github page due to manifest.json,
+// so these checks don't need to include that.
+const prUrlRegex = /\/[^\/]+\/[^\/]+\/pull\/\d+\/files.*/
+const fileUrlRegex = /\/[^\/]+\/[^\/]+\/blob\/[^\/]+\/.*/
+
+export function isFileUrl(url: string): boolean {
+  return fileUrlRegex.test(url);
+}
+
+export function isPrUrl(url: string): boolean {
+  return prUrlRegex.test(url);
+}

src/content/github/file/main.tsx

@@ -12,7 +12,6 @@ import {
   FileCoverageReport,
   FileCoverageReportResponse,
   FileMetadata,
-  MessageType,
 } from "src/types";
 import {
   componentsStorageKey,
@@ -34,6 +33,7 @@ import {
   getBranchReport,
 } from "../common/fetchers";
 import { print } from "src/utils";
+import { isFileUrl } from "../common/utils";
 
 const globals: {
   coverageReport?: FileCoverageReport;
@@ -60,15 +60,14 @@ function init(): Promise<void> {
 }
 
 async function main(): Promise<void> {
-  let metadata: FileMetadata;
-
-  try {
-    metadata = await getMetadata(document.URL);
-  } catch (e) {
+  if (!isFileUrl(document.URL)) {
     print("file not detected at current URL");
     return;
   }
 
+  let metadata: FileMetadata;
+  metadata = await getMetadata(document.URL);
+
   globals.coverageButton = createCoverageButton();
 
   process(metadata).catch((e) => {

src/content/github/pr/main.tsx

@@ -4,7 +4,7 @@ import _ from "lodash";
 
 import "src/basscss.css";
 import { displayChange } from "src/utils";
-import { CoverageStatus, MessageType, PullCoverageReport } from "src/types";
+import { CoverageStatus, PullCoverageReport } from "src/types";
 import {
   animateAndAnnotateLines,
   clearAnimation,
@@ -14,6 +14,7 @@ import { lineSelector } from "./constants";
 import { colors } from "../common/constants";
 import { print } from "src/utils";
 import { getPRReport } from "../common/fetchers";
+import { isPrUrl } from "../common/utils";
 
 const globals: {
   coverageReport?: PullCoverageReport;
@@ -26,7 +27,13 @@ async function main() {
 }
 
 async function execute() {
+  if (!isPrUrl(document.URL)) {
+    print("PR not detected at current URL");
+    return;
+  }
+
   const urlMetadata = getMetadataFromURL();
+
   if (!urlMetadata) {
     print("PR not detected at current URL");
     return;