eslint: Fix unicorn/prefer-optional-catch-binding.

https://github.com/sindresorhus/eslint-plugin-unicorn/blob/master/docs/rules/prefer-optional-catch-binding.md

Signed-off-by: Anders Kaseorg <anders@zulip.com>

static/js/hash_util.js

@@ -66,7 +66,7 @@ exports.decodeHashComponent = function (str) {
         // that the url is invalid.
         // TODO: Show possible valid urls to the user.
         return decodeURIComponent(str.replace(/\./g, "%"));
-    } catch (e) {
+    } catch {
         ui_report.error(i18n.t("Invalid URL"), undefined, $("#home-error"), 2000);
         return "";
     }

static/js/localstorage.js

@@ -5,7 +5,7 @@ const ls = {
     parseJSON(str) {
         try {
             return JSON.parse(str);
-        } catch (err) {
+        } catch {
             return undefined;
         }
     },
@@ -169,7 +169,7 @@ let warned_of_localstorage = false;
 localstorage.supported = function supports_localstorage() {
     try {
         return window.localStorage !== undefined && window.localStorage !== null;
-    } catch (e) {
+    } catch {
         if (!warned_of_localstorage) {
             blueslip.error(
                 "Client browser does not support local storage, will lose socket message on reload",

static/js/portico/integrations_dev_panel.js

@@ -84,7 +84,7 @@ function get_custom_http_headers() {
         try {
             // Let JavaScript validate the JSON for us.
             custom_headers = JSON.stringify(JSON.parse(custom_headers));
-        } catch (err) {
+        } catch {
             set_results_notice("Custom HTTP headers are not in a valid JSON format.", "warning");
             return undefined;
         }
@@ -189,7 +189,7 @@ function handle_unsuccessful_response(response) {
         const status_code = response.statusCode().status;
         response = JSON.parse(response.responseText);
         set_results_notice("Result: " + "(" + status_code + ") " + response.msg, "warning");
-    } catch (err) {
+    } catch {
         // If the response is not a JSON response, then it is probably
         // Django returning an HTML response containing a stack trace
         // with useful debugging information regarding the backend
@@ -262,7 +262,7 @@ function send_webhook_fixture_message() {
             // Let JavaScript validate the JSON for us.
             body = JSON.stringify(JSON.parse(body));
             is_json = true;
-        } catch (err) {
+        } catch {
             set_results_notice("Invalid JSON in fixture body.", "warning");
             return;
         }

static/js/submessage.js

@@ -119,7 +119,7 @@ exports.handle_event = function (submsg) {
 
     try {
         data = JSON.parse(submsg.content);
-    } catch (err) {
+    } catch {
         blueslip.error("server sent us invalid json in handle_event: " + submsg.content);
         return;
     }

static/js/upload.js

@@ -164,7 +164,7 @@ exports.upload_files = function (uppy, config, files) {
                 type: file.type,
                 data: file,
             });
-        } catch (error) {
+        } catch {
             // Errors are handled by info-visible and upload-error event callbacks.
             break;
         }

static/js/util.js

@@ -143,7 +143,7 @@ exports.make_strcmp = function () {
     try {
         const collator = new Intl.Collator();
         return collator.compare;
-    } catch (e) {
+    } catch {
         // continue regardless of error
     }
 

static/shared/js/fenced_code.js

@@ -78,7 +78,7 @@ function wrap_tex(tex) {
         return katex.renderToString(tex, {
             displayMode: true,
         });
-    } catch (ex) {
+    } catch {
         return '<span class="tex-error">' + _.escape(tex) + "</span>";
     }
 }