How to negate angular pattern/regex [duplicate]

Question

I have the following code

pattern="^\s+$"

I need to negate this, because as of now I got error when I put a letter, but it should only show error IF there is only white space.

I tried using ?! but it shows an error

empty or only space should return the error. If I write anything like 100space and a letter, this should be ok — YoloSwaggg
– YoloSwaggg, Commented Jan 8, 2019 at 7:58

Allan · Accepted Answer · 2019-01-08 08:02:34Z

0

You can use the following regex:

^(?: *[^\s] *)+$

answered Jan 8, 2019 at 8:02

Allan

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Comments

The fourth bird · Accepted Answer · 2019-01-08 08:14:38Z

0

If you want to use a negative lookahead (?!, you could check if from the start till the end of the string there are no whitespace characters:

pattern="^(?!\s*$)[\s\S]+$"

That will match

^ Start of string
(?!\s*$) Negative lookahead, assert that what follows is not 0+ whitespace characters and end of string
[\s\S]+ Match 1+ times any character including new lines
$ End of string

answered Jan 8, 2019 at 8:02

The fourth bird

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