Warning: String.x is deprecated; use String.prototype.x instead
The JavaScript warning about string generics occurs in Firefox versions prior to 68. String generics have been removed starting with Firefox 68, and these warning messages are obsolete.
Message
Warning: String.charAt is deprecated; use String.prototype.charAt instead Warning: String.charCodeAt is deprecated; use String.prototype.charCodeAt instead Warning: String.concat is deprecated; use String.prototype.concat instead Warning: String.contains is deprecated; use String.prototype.contains instead Warning: String.endsWith is deprecated; use String.prototype.endsWith instead Warning: String.includes is deprecated; use String.prototype.includes instead Warning: String.indexOf is deprecated; use String.prototype.indexOf instead Warning: String.lastIndexOf is deprecated; use String.prototype.lastIndexOf instead Warning: String.localeCompare is deprecated; use String.prototype.localeCompare instead Warning: String.match is deprecated; use String.prototype.match instead Warning: String.normalize is deprecated; use String.prototype.normalize instead Warning: String.replace is deprecated; use String.prototype.replace instead Warning: String.search is deprecated; use String.prototype.search instead Warning: String.slice is deprecated; use String.prototype.slice instead Warning: String.split is deprecated; use String.prototype.split instead Warning: String.startsWith is deprecated; use String.prototype.startsWith instead Warning: String.substr is deprecated; use String.prototype.substr instead Warning: String.substring is deprecated; use String.prototype.substring instead Warning: String.toLocaleLowerCase is deprecated; use String.prototype.toLocaleLowerCase instead Warning: String.toLocaleUpperCase is deprecated; use String.prototype.toLocaleUpperCase instead Warning: String.toLowerCase is deprecated; use String.prototype.toLowerCase instead Warning: String.toUpperCase is deprecated; use String.prototype.toUpperCase instead Warning: String.trim is deprecated; use String.prototype.trim instead Warning: String.trimLeft is deprecated; use String.prototype.trimLeft instead Warning: String.trimRight is deprecated; use String.prototype.trimRight instead
Error type
Warning. JavaScript execution won't be halted.
What went wrong?
The non-standard generic String
methods are deprecated and have been
removed in Firefox 68 and later. String generics provide String
instance
methods on the String
object allowing String
methods to be
applied to any object.
Examples
Deprecated syntax
const num = 15;
String.replace(num, /5/, "2");
Standard syntax
const num = 15;
String(num).replace(/5/, "2");