RegExp \B Metacharacter
Find the first occurrence of "LO", NOT at the beginning of a word:
let text = "HELLO, LOOK AT YOU!";
let pattern = /\BLO/;
Try it Yourself »
Description
The \B metacharacter matches NOT at the beginning/end of a word.
Search for the pattern LO, not at the beginning of a word like this:
\BLO
Search for the pattern LO, not at the end of a word like this:
LO\B
Syntax
new RegExp("\\Bregexp")
or simply:
/\Bregexp/
Syntax with modifiers
new RegExp("\\Bregexp", "g")
or simply:
/\Bregexp/g
Boundary Assertion:
The ^ Metacharacter (Boundary beginning)
The $ Metacharacter (Boundary end)
The \b Metacharacter (Word boundary)
The \B Metacharacter (Non-word boundary)
More Examples
Example
Find the first occurrence of "LO", NOT at the END of a word:
let text = "HELLO, LOOK AT YOU";
let pattern = /LO\B/;
Try it Yourself »
Regular Expression Methods
Regular Expression Search and Replace can be done with different methods.
These are the most common:
String Methods
| Method | Description |
|---|---|
| match(regex) | Returns an Array of results |
| matchAll(regex) | Returns an Iterator of results |
| replace(regex) | Returns a new String |
| replaceAll(regex) | Returns a new String |
| search(regex) | Returns the index of the first match |
| split(regex) | Returns an Array of results |
RegExp Methods
| Method | Description |
|---|---|
| regex.exec() | Returns an Iterator of results |
| regex.test() | Returns true or false |
Browser Support
/\B/ is an ECMAScript1 (JavaScript 1997) feature.
It is supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera | IE |
| Yes | Yes | Yes | Yes | Yes | Yes |
