ThestartsWith() method ofString values determines whether this string begins with the characters of a specified string, returningtrue orfalse as appropriate.

Try it

const str = "Saturday night plans";console.log(str.startsWith("Sat"));// Expected output: trueconsole.log(str.startsWith("Sat", 3));// Expected output: false

Syntax

startsWith(searchString)startsWith(searchString, position)

Parameters

searchString

The characters to be searched for at the start of this string. Cannotbe a regex. All values that are not regexes arecoerced to strings, so omitting it or passingundefined causesstartsWith() to search for the string"undefined", which is rarely what you want.

positionOptional

The start position at whichsearchString is expected to be found (the index ofsearchString's first character). Defaults to0.

Return value

true if the given characters are found at the beginning of the string, including whensearchString is an empty string; otherwise,false.

Exceptions

TypeError

Thrown ifsearchStringis a regex.

Description

This method lets you determine whether or not a string begins with another string. This method is case-sensitive.

Examples

Using startsWith()

const str = "To be, or not to be, that is the question.";console.log(str.startsWith("To be")); // trueconsole.log(str.startsWith("not to be")); // falseconsole.log(str.startsWith("not to be", 10)); // true

Specifications

Browser compatibility

See also

• Polyfill ofString.prototype.startsWith incore-js
• es-shims polyfill ofString.prototype.startsWith
• String.prototype.endsWith()
• String.prototype.includes()
• String.prototype.indexOf()
• String.prototype.lastIndexOf()