Negate RegExp

[sunupf]

Hi,

I trying to generate based on /^((?![0-9]).)*$/ , it shoud be valid if there is no number on the string, and I try this expression on randexp

$ node -i

var randexp = require('randexp')
new randexp(/^((?![0-9]).)*$/).gen()
';vpqBpM+eBJS2H#.W#G:q3tMdwMaU\uTJ,bhG'

but when I test the result it's return false.

/^((?![0-9]).)*$/.test(';vpqBpM+eBJS2H#.W#G:q3tMdwMaU\uTJ,bhG')
false

Thanks,

[fent]

I am not sure if this is an error with randexp, but I'm confused with the use of ?! with nothing preceding it, and why it would compile.

Why not use /^[^0-9]*$/?

[sunupf]

actually 0-9 is just for test, i want replace it using another pattern which can be complex.

I just try too negate regexp that user inputed. that's why I use ?!

[fent]

Right now, randexp ignores groups that use the x(?!y) syntax. it prints a blank string for them. should it be printing something that does NOT match whatever is inside?

It's a confusing rule, /x(?!y)/.test('x') is true, as well as /x(?!y)/.test('xz'). It looks like x would be fine by itself if there is nothing after the group, otherwise it has to make sure whatever is after it also does not match the group.