Question

Inline comments works when a string passed to the RegExp constructor:

RegExp("foo"/*bar*/).test("foo")

but not with an expression. Is there any equivalent or alternative in JavaScript to emulate x-mode for the RegExp object?

Answer 1

Javascript supports neither the x modifier, nor inline comments (?#comment). See here.

I guess, the best you can do, is to use the RegExp constructor and write every line in e separate string and concatenate them (with comments between the strings):

RegExp(
    "foo" + // match a foo
    "bar" + // followed by a bar
    "$"     // at the end of the string
).test("somefoobar");