String

`String.prototype.startsWith`

Determines whether a string begins with the characters of a specified string

Syntax

JavaScript

string.startsWith(searchString, position?)

Parameters

Parameter	Type	Description
searchString	string	The characters to be searched for at the start
position	number	Position at which to begin searching

Return Value

true if the string begins with the search string, false otherwise

Examples

Basic Usage

const str = 'Hello World';
console.log(str.startsWith('Hello')); // true
console.log(str.startsWith('World')); // false

Practical Example

const url = 'https://example.com';
if (url.startsWith('https://')) {
  console.log('Secure connection');
}

Advanced Usage

const filename = 'readme.md';
console.log(filename.startsWith('read')); // true

Understanding String.prototype.startsWith

The String.prototype.startsWith method in JavaScript determines whether a string begins with the characters of a specified string. It belongs to the String object and is one of the most widely used methods for working with string values in modern JavaScript and TypeScript applications.

The method signature is string.startsWith(searchString, position?). It accepts 2 parameters: searchString, position. When called, it returns true if the string begins with the search string, false otherwise. Understanding when and how to use startsWith() helps you write more expressive, readable code.

Common use cases for String.prototype.startsWith include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like string-endswith, string-includes, string-indexof, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for String.prototype.startsWith is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.