Are there JavaScript equivalents of the Vim regular expression start and end of word atoms "\<" and "\>"?

Question

I know most regular expression engines, including the one in JavaScript have \b to match a word boundary, be it at either the start or end of a word.

But Vim also has two more specific regular expression atoms:

• \< matches only the word boundary at the start of a word
• \> matches only the word boundary at the end of a word

Does JavaScript have an equivalent to these atoms, and if not is there a way to express their more precise semantics some other way?

Byroad

Actually I just started to worry that \< and \> are actually from Vim... maybe they're from both. Checking now... – Byroad

But won't any word boundary be both the start of some word and the end of another word? What is the distinction you're trying to handle? – Sidewalk

@MarkReed, no, because a word boundary does match only the position directly before/after a word and NOT e.g. the whitespace before/after the word. – Fussbudget

Answer 1

As far as I know there is nothing predefined. But what you can do is, to add a lookahead to the word boundary, to check if it is the start or the end of the word.

\< would be then \b(?=\w). This checks if after the word boundary a word character is following ==> start of the word. See this as example on regexr

\> would be then \b(?!\w). This checks if after the word boundary not a word character is following ==> end of the word

Fussbudget

+1, but you should use (?!\w) instead of (?=\W) for the second case. – Janettjanetta

It's actually not just more clear - your solution would not have matched a word boundary at the end of the string. – Janettjanetta

@Jan-StefanJanetzky Uh, no. Just (?!\w). Or (?=\W|$), but that's awkward. – Janettjanetta