String.prototype.search()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The search()
method of String
values executes a search for a match between a regular expression and this string, returning the index of the first match in the string.
Try it
Syntax
search(regexp)
Parameters
regexp
-
A regular expression object, or any object that has a
Symbol.search
method.If
regexp
is not aRegExp
object and does not have aSymbol.search
method, it is implicitly converted to aRegExp
by usingnew RegExp(regexp)
.
Return value
The index of the first match between the regular expression and the given string, or -1
if no match was found.
Description
The implementation of String.prototype.search()
itself is very simple — it simply calls the Symbol.search
method of the argument with the string as the first parameter. The actual implementation comes from RegExp.prototype[Symbol.search]()
.
The g
flag of regexp
has no effect on the search()
result, and the search always happens as if the regex's lastIndex
is 0. For more information on the behavior of search()
, see RegExp.prototype[Symbol.search]()
.
When you want to know whether a pattern is found, and also know its index within a string, use search()
.
- If you only want to know if it exists, use the
RegExp.prototype.test()
method, which returns a boolean. - If you need the content of the matched text, use
String.prototype.match()
orRegExp.prototype.exec()
.
Examples
Using search()
The following example searches a string with two different regex objects to show a successful search (positive value) vs. an unsuccessful search (-1
).
const str = "hey JudE";
const re = /[A-Z]/;
const reDot = /[.]/;
console.log(str.search(re)); // returns 4, which is the index of the first capital letter "J"
console.log(str.search(reDot)); // returns -1 cannot find '.' dot punctuation
Specifications
Specification |
---|
ECMAScript Language Specification # sec-string.prototype.search |
Browser compatibility
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