# Input Validation

CommandPrompter's input validation uses regex to check for the input. To use it, you have to define an `input validator` in the `prompt-config.ym` under the key `Input-Validation` and use it as a `prompt argument` for your `prompt`

#### Input Validator

An input validator could have any key. But under that key, there must be an `Alias` and at least one[#validator](#validator "mention"). There's also an optional key that you can set called `Err-Message`. The following is an example of input validators that's included with CommandPrompter by default.

#### Validators

| Validator     | Key           | Description                                                                    |
| ------------- | ------------- | ------------------------------------------------------------------------------ |
| Regex         | Regex         | validates an input by checking if it matches the defined regular expression    |
| Online Player | Online-Player | validates an input by checking if it's a username of one of the online players |

```yml
Input-Validation:
  Integer-Sample:
    Alias: is
    Regex: '^\d+'
    Err-Message: '&cPlease enter a valid integer!'
  Alpha-Sample:
    Alias: as
    Regex: '[A-Za-z ]+'
    Err-Message: '&cInput must only consist letters of the alphabet!'
  Online-Validator:
    Alias: ov
    Online-Player: true
    Err-Message: '&cThat player is not online!`
```

#### Usage

Once you have input validators defined, you can use them by using the prompt argument `-iv:<validator alias>`. For example:

```
/command <-iv:is integers only!>
/command <-iv:as alphas only!>
/command <-iv:ov online players only!>
```

Since it's a prompt argument, it won't affect other prompt's input validation so you can have something like the following:

```
/command <-iv:is enter only integers> <-iv:as enter only alphas> <-iv:ov online players only!>
```

If it doesn't pass the regex test, the plugin sends the error message and sends the prompt again.

To learn more about regular expressions click [here](https://github.com/Varunram/Awesome-Regex-Resources)


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