regEx text replace using | and () capture issue

Question

I'm using javaScript RegEx literals to replace parts of a string, i want to use | to check for different types of patterns that may occur and () to capture a part of the match i want to replace. it doesn't seem to work though, why is this?

here's my current regEx:

testText.replace(/(\w)\s+\w$|(\w)\s+$|\w+(\w)$/g, "$1...")

I'm guessing somethings wrong with it: here's want i want to acheieve:

given "xx" i expect:

  "x..."

given "x " I expect:

   "x...

given "werfdsdfasd" (word with no space) I expect:

   "werfdsdfasd..."

Answer 1

The problem is that you have 3 capture groups and you always reference the first one.

Try this: (\\w+)(?:\\s+\\w$|\\s+$|$)

Demo

Answer 2

因此，您想捕获空格或行尾之前的所有内容。

(\w+)(\s+.*$|$)