CODEWITHSUNDEEP
javascriptangularjsregexangularjs-ng-pattern
Tarun Dugar
Tarun Dugar

Reputation: 8971

ng-pattern should not match supplied pattern

In ng-pattern we have the option of specifying that the field should match a specific pattern.

How can we specify that it should NOT match the specified pattern?

Example,

<input type="text" ng-pattern="/[*|\":<>[\]{}`()';@&$]/" />

Here, I DONT want the field to match the pattern. On the contrary, I want to show error if the pattern matches.

Upvotes: 5

Views: 2743

Answers (2)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626691

In order to check if a string does not have some substring, you can use a string-start-anchored lookahead:

/^(?!.*[*|\x22:<>[\]{}`()';@&$])/

See demo

In AngularJS, the pattern does not have to match the entire string if a RegExp object is passed (the one with delimiters), so this regex suits the current purpose well (just check if a condition is true or false).

Note that the commonly used tempered greedy token solution ^(?:(?![*|\x22:<>\[\]{}`()';@&$]).)*$ (see demo) can be used, too, but it is less efficient since each position in the input string is checked.

Also, it is convenient to use \x22 to match a double quote in the ng-pattern value.

Upvotes: 1

Darin Dimitrov
Darin Dimitrov

Reputation: 1038710

You could use a negative lookaround ((?!pattern)) to negate your regex:

ng-pattern="/(?![*|\":<>[\]{}`()';@&$])/"

Upvotes: 3

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