# Typed input of type 're' (i.e. regular expresssion)
**URL:** https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891
**Category:** Developing Nodes
**Created:** [13 December 2024 06:50 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891 "2024-12-13T06:50:12Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)
#### Post date: [13 December 2024 06:50 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/1 "2024-12-13T06:50:12Z")
Hi folks,
I want to enter a text into a typedinput, but there should be a visible indication when the text does not match a specified regular expression.
I see that the [typedinput](https://nodered.org/docs/api/ui/typedInput/) allows to use regular expressions:
Can that be used for my purpose? And could anybody provide a simple example? I certainly must be overthinking it, but I am not sure how to specify my regex...
Thanks!!
Bart
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [13 December 2024 07:11 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/2 "2024-12-13T07:11:14Z")
Not quite following Bart. Can you provide an annotated screen shot describing what you are seeing and what you expect to see?
---
### Author:  [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)
#### Post date: [13 December 2024 07:57 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/3 "2024-12-13T07:57:16Z")
Hey Steve,
I have no screen yet for this part. Currently I have a simple text input element, with a regex to validate the input based on some pattern. For example:
```auto
```
Now I would like to do something similar with a TypedInput. So I thought that I could use identifier _ **"re"** _ instead of _ **"str"** _ (see screenshot above).
But from your response I assume the "re" identifier is used for a complete other purpose?
Thanks!
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [13 December 2024 08:12 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/4 "2024-12-13T08:12:48Z")
So, the `re` input is to provide a means of letting a user enter a regex, not for validating users input.
If you simply want to validate user input you can do that use a validator (you can even use regex in your validation).
```auto
defaults: {
myString: {
value: "",
validate: RED.validators.regex(/[A-Za-z]{3}/)
},
...
}
```
Perhaps if you provide context to the task at hand I can better help?
---
### Author:  [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)
#### Post date: [13 December 2024 17:03 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/5 "2024-12-13T17:03:59Z")
> [@Steve-Mcl](#):
>
> the `re` input is to provide a means of letting a user enter a regex
Ah that explains my confusion. Indeed I thought it was used for validating an input based on a regex, and I had no idea where to specify that regex 🙄
So my case is this: some property needs to be a string, that needs to contain a pattern. The string can be hardcoded in the config screen, or injected via an input message. So the types of my TypedInput are `["str", "msg"]`. But in the config screen the pattern matching test should only be applied when type is "str", not for "msg".
While writing my problem down here, I assume you are going to tell me that I need a validation function that only checks the pattern if type is "str"...
---
### Author:  [@knolleary](https://discourse.nodered.org/u/knolleary)
#### Post date: [13 December 2024 17:09 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/6 "2024-12-13T17:09:46Z")
You can define your own type that is a copy of the `str` type, but with your added custom validation rule:
```auto
types: [
{
value: "str",
label: "Bart's String",
icon: "red/images/typedInput/az.svg",
validate: function (value, opt) {
// return true/false depending on if `value` is valid or not
}
},
'msg'
]
```
---
### Author:  [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)
#### Post date: [13 December 2024 17:21 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/7 "2024-12-13T17:21:00Z")
Ah ok, that is indeed much more readable compare to a general validation function that depends on the type.
Thanks guys and enjoy your weekend!
---
### Author:  [@GogoVega](https://discourse.nodered.org/u/GogoVega)
#### Post date: [14 December 2024 09:51 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/8 "2024-12-14T09:51:33Z")
I add that you can also return a string which will be the error message displayed by the input.
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [12 February 2025 09:51 UTC](https://discourse.nodered.org/t/typed-input-of-type-re-i-e-regular-expresssion/93891/9 "2025-02-12T09:51:40Z")
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