StringprototypestartsWith
String.prototype.startsWith is a JavaScript method that determines whether a string begins with the characters of a specified string, returning true or false. It is a standard part of the String prototype introduced in ECMAScript 2015 (ES6) and is widely supported in modern environments, including browsers and Node.js.
The method takes two parameters. The first, searchString, is the string to look for at the start
startsWith is a case-sensitive prefix check and does not interpret searchString as a regular expression. It
- "Hello world".startsWith("Hello") -> true
- "Hello world".startsWith("hello") -> false
- "abcdef".startsWith("def", 3) -> true
- "abcdef".startsWith("", 2) -> true
Performance and compatibility considerations: in environments without native support, a polyfill can implement equivalent behavior, typically