String.fromCodePoint()
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 String.fromCodePoint()
static method returns a string created from the specified sequence of code points.
Try it
Syntax
String.fromCodePoint()
String.fromCodePoint(num1)
String.fromCodePoint(num1, num2)
String.fromCodePoint(num1, num2, /* …, */ numN)
Parameters
num1
, …,numN
-
An integer between
0
and0x10FFFF
(inclusive) representing a Unicode code point.
Return value
A string created by using the specified sequence of code points.
Exceptions
RangeError
-
Thrown if
numN
is not an integer, is less than0
, or is greater than0x10FFFF
after being converted to a number.
Description
Because fromCodePoint()
is a static method of String
, you always use it as String.fromCodePoint()
, rather than as a method of a String
value you created.
Unicode code points range from 0
to 1114111
(0x10FFFF
). In UTF-16, each string index is a code unit with value 0
– 65535
. Higher code points are represented by a pair of 16-bit surrogate pseudo-characters. Therefore, fromCodePoint()
may return a string whose length
(in UTF-16 code units) is larger than the number of arguments passed. For information on Unicode, see UTF-16 characters, Unicode code points, and grapheme clusters.
Examples
Using fromCodePoint()
Valid input:
String.fromCodePoint(42); // "*"
String.fromCodePoint(65, 90); // "AZ"
String.fromCodePoint(0x404); // "\u0404" === "Є"
String.fromCodePoint(0x2f804); // "\uD87E\uDC04"
String.fromCodePoint(194564); // "\uD87E\uDC04"
String.fromCodePoint(0x1d306, 0x61, 0x1d307); // "\uD834\uDF06a\uD834\uDF07"
Invalid input:
String.fromCodePoint("_"); // RangeError
String.fromCodePoint(Infinity); // RangeError
String.fromCodePoint(-1); // RangeError
String.fromCodePoint(3.14); // RangeError
String.fromCodePoint(3e-2); // RangeError
String.fromCodePoint(NaN); // RangeError
Compared to fromCharCode()
String.fromCharCode()
cannot return supplementary characters (i.e. code points 0x010000
– 0x10FFFF
) by specifying their code point. Instead, it requires the UTF-16 surrogate pair in order to return a supplementary character:
String.fromCharCode(0xd83c, 0xdf03); // Code Point U+1F303 "Night with
String.fromCharCode(55356, 57091); // Stars" === "\uD83C\uDF03"
String.fromCodePoint()
, on the other hand, can return 4-byte supplementary characters, as well as the more common 2-byte BMP characters, by specifying their code point (which is equivalent to the UTF-32 code unit):
String.fromCodePoint(0x1f303); // or 127747 in decimal
Specifications
Specification |
---|
ECMAScript Language Specification # sec-string.fromcodepoint |
Browser compatibility
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