String.prototype.startsWith()
The startsWith()
method determines whether a string begins with the characters of a specified string, returning true
or false
as appropriate.
Try it
Syntax
js
startsWith(searchString)
startsWith(searchString, position)
Parameters
searchString
-
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
causesstartsWith()
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 ofsearchString
's first character). Defaults to0
.
Return value
true
if the given characters are found at the beginning of the string, including when searchString
is an empty string; otherwise, false
.
Exceptions
TypeError
-
Thrown if
searchString
is 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()
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
Specifications
Specification |
---|
ECMAScript Language Specification # sec-string.prototype.startswith |
Browser compatibility
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