--- a/toolkit/components/extensions/ext-browserSettings.js
+++ b/toolkit/components/extensions/ext-browserSettings.js
@@ -373,29 +373,34 @@ this.browserSettings = class extends Ext
                 "permissions.default.desktop-notification", null);
             return prefValue === PERM_DENY_ACTION;
           }),
         useDocumentColors: Object.assign(
           getSettingsAPI(
             extension, "useDocumentColors",
             () => {
               let prefValue = Services.prefs.getIntPref("browser.display.document_color_use");
-              return prefValue === 1 ? "never" : (prefValue === 2 ? "always" : "high-contrast-only");
+              if (prefValue === 1) {
+                return "never";
+              } else if (prefValue === 2) {
+                return "always";
+              }
+              return "high-contrast-only";
             }
           ),
           {
             set: details => {
               if (!["never", "always", "high-contrast-only"].includes(details.value)) {
                 throw new ExtensionError(
                   `${details.value} is not a valid value for useDocumentColors.`);
               }
               let prefValue = 0; // initialize to 0 - auto/high-contrast-only
-              if ("never" === details.value) {
+              if (details.value === "never") {
                 prefValue = 1;
-              } else if ("always" === details.value) {
+              } else if (details.value === "always") {
                 prefValue = 2;
               }
               return ExtensionPreferencesManager.setSetting(
                 extension.id, "useDocumentColors", prefValue);
             },
           }
         ),
       },