String.prototype.startsWith()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2015.

The startsWith() method of String values determines whether this string begins with the characters of a specified string, returning true or false as appropriate.

Try it

const str = "Saturday night plans";

console.log(str.startsWith("Sat"));
// Expected output: true

console.log(str.startsWith("Sat", 3));
// Expected output: false

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

position Optional

The start position at which searchString is expected to be found (the index of searchString's first character). Defaults to 0.

js
const str = "To be, or not to be, that is the question.";

console.log(str.startsWith("To be")); // true
console.log(str.startsWith("not to be")); // false
console.log(str.startsWith("not to be", 10)); // true