JavaScript String isWellFormed()
Examples
let text = "Hello world!";
let result = text.isWellFormed();
Try it Yourself »
let text = "Hello World \uD800";
let result = text.isWellFormed();
Try it Yourself »
Description
The isWellFormed() method returns true
if a string is well formed.
Otherwise it returns false.
A string is well formed if does not contain lone surrogates.
Lone Surrogates
A Lone surrogate is a Unicode surrogate code that is not a part of a valid surrogate pair, used to represent characters in UTF-16 encoding.
Syntax
string.isWellFormed()
Parameters
| NONE | 
Return Value
| Type | Description | 
| Boolean | true if the string is well formed,
otherwise false. | 
Browser Support
isWellFormed() is a JavaScrip 2024 feature.
ES 2024 is fully supported in all modern browsers since March 2024:
| Chrome 117  | 
    Edge 117  | 
    Firefox 119  | 
    Safari 17.4  | 
    Opera 103  | 
  
| Sep 2023 | Sep 2023 | Oct 2023 | Okt 2024 | May 2023 |