Lookbehind javascript regexp

Question

I'm trying to replace some string using pattern but I have no idea how to check if there is dot before string. It should be negative for .some and positive for some

var a = "some.string is replaced  and .some.string5 is not"
a.replace(new RegExp("some", "g"), "replaced")

It should give result replaced.string is replaced and .some.string5 is not THX

Possible duplicate of javascript regex - look behind alternative? — Martin Cup
– Martin Cup, Commented Dec 12, 2016 at 18:42

Martin Cup · Accepted Answer · 2016-12-12 18:37:22Z

2

As Javascript hasn't lookbehinds implemented you can match it normally and replace the preceding character with itself with a backreference: a = a.replace(new RegExp("([^\.]|^)some\.string", "g"), "$1replaced");

edited Dec 12, 2016 at 18:37

answered Dec 12, 2016 at 17:49

Martin Cup

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2 Comments

alexhughesking Over a year ago

Lookbehind is not supported in javascript.

Martin Cup Over a year ago

Thank you. I wasn't aware of that. I edited my answer.

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