String.prototype.replaceAll()
The replaceAll()
method returns
a new string with all matches of a pattern
replaced by a
replacement
. The pattern
can be a string or a
RegExp
, and the replacement
can be a string or a function to
be called for each match.
The original string is left unchanged.
Syntax
replaceAll(regexp, newSubstr)
replaceAll(regexp, replacerFunction)
replaceAll(substr, newSubstr)
replaceAll(substr, replacerFunction)
Note: When using a `regexp` you have to set the global ("g") flag; otherwise, it
will throw a TypeError
: "replaceAll must be called with a global RegExp".
Parameters
regexp
(pattern)-
A
RegExp
object or literal with the global flag. The matches are replaced withnewSubstr
or the value returned by the specifiedreplacerFunction
. A RegExp without the global ("g") flag will throw aTypeError
: "replaceAll must be called with a global RegExp". substr
-
A
String
that is to be replaced bynewSubstr
. It is treated as a literal string and is not interpreted as a regular expression. newSubstr
(replacement)-
The
String
that replaces the substring specified by the specifiedregexp
orsubstr
parameter. A number of special replacement patterns are supported; see the "Specifying a string as a parameter" section below. replacerFunction
(replacement)-
A function to be invoked to create the new substring to be used to replace the matches to the given
regexp
orsubstr
. The arguments supplied to this function are described in the "Specifying a function as a parameter" section below.
Return value
A new string, with all matches of a pattern replaced by a replacement.
Description
This method does not change the calling String
object. It returns a new string.
Specifying a string as a parameter
The replacement string can include the following special replacement patterns:
Pattern | Inserts |
---|---|
$$ |
Inserts a "$" . |
$& |
Inserts the matched substring. |
$` |
Inserts the portion of the string that precedes the matched substring. |
$' |
Inserts the portion of the string that follows the matched substring. |
$n |
Where n is a positive integer less than 100, inserts the n th parenthesized submatch string, provided the first argument was a RegExp object. Note that this is 1 -indexed. |
Specifying a function as a parameter
You can specify a function as the second parameter. In this case, the function will be invoked after the match has been performed. The function's result (return value) will be used as the replacement string. (Note: The above-mentioned special replacement patterns do not apply in this case.)
Note that if the first argument of an replaceAll()
invocation is a RegExp
object or regular expression literal, the function will be invoked multiple times.
The arguments to the function are as follows:
Possible name | Supplied value |
---|---|
match |
The matched substring. (Corresponds to $& above.) |
p1, p2, ... |
The nth string found by a parenthesized capture group, provided the first argument to replaceAll() was a RegExp object. (Corresponds to $1 , $2 , etc. above.) For example, if /(\a+)(\b+)/ , was given, p1 is the match for \a+ , and p2 for \b+ . |
offset |
The offset of the matched substring within the whole string being examined. (For example, if the whole string was 'abcd' , and the matched substring was 'bc' , then this argument will be 1 .) |
string |
The whole string being examined. |
namedGroups |
An object of all named capturing groups. The keys are the names of the capturing groups and each value is the substring matching the named capture group. If the regular expression doesn't contain any capturing groups, namedGroups is undefined. |
(The exact number of arguments depends on whether the first argument is a
RegExp
object—and, if so, how many parenthesized submatches it specifies.)
Examples
Using replaceAll
'aabbcc'.replaceAll('b', '.');
// 'aa..cc'
Non-global regex throws
When using a regular expression search value, it must be global. This won't work:
'aabbcc'.replaceAll(/b/, '.');
TypeError: replaceAll must be called with a global RegExp
This will work:
'aabbcc'.replaceAll(/b/g, '.');
"aa..cc"
Specifications
Specification |
---|
ECMAScript Language Specification # sec-string.prototype.replaceall |
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