StringprototypestartsWithsearchString

StringprototypestartsWithsearchString refers to the JavaScript method String.prototype.startsWith, which checks whether a string begins with a given substring. It returns a boolean: true if the string starts with searchString, otherwise false.

Syntax: String.prototype.startsWith(searchString[, position]). The searchString is converted to a string. position is optional and specifies the index in the calling string at which to begin the check; it defaults to 0. If position is negative, it is treated as 0. If position is greater than the string’s length, the result is false.

Parameters: searchString is the substring to look for at the start of the string. position allows offsetting the starting point for the check.

Return value: A boolean indicating whether the string starts with searchString at the given position.

Examples: 'abcdef'.startsWith('abc') returns true. 'abcdef'.startsWith('bc', 1) returns true. 'abcdef'.startsWith('def', 3) returns true. 'abc'.startsWith('', 2) returns true.

Compatibility and polyfills: Introduced in ES2015 (ES6) and supported in all modern browsers and Node.js. In older environments, a polyfill can provide equivalent functionality.

See also: includes, endsWith, indexOf.

This article describes the behavior and usage of StringprototypestartsWithsearchString, aligning with the standard JavaScript String.prototype.startsWith method.