go-forms

A simple form builder for Go.

Features

• Simple form definition
• Form validation
• Form rendering (currently fyne only)
• Display conditions for form fields
• Many form field types

Usage

Look at the example directory for a simple example. You can run the example with go run example/example.go.

Field types

FieldBase

The base field type that all other fields inherit from. DO NOT USE DIRECTLY.

Properties:

• Id (string): Unique identifier for the field.
• DisplayCondition (string): Condition for displaying the field. If the condition is not met, the field will not be displayed.
• Validators ([]Validator): List of validators for the field.
• Value (string): Value of the field.
• form (*Form): Reference to the form that the field belongs to.
• error (error): Error message for the field if validation fails.

Available display conditions

• AlwaysDisplay: Always display the field.
• CustomDisplayCondition: Custom display condition. Takes a function with the prop field any that returns a boolean as the Condition.
• IsValidDisplayCondition: Display the field if the fields given in FieldIds are valid.
• IsInvalidDisplayCondition: Display the field if the fields given in FieldIds are invalid.
• AllFieldsValidDisplayCondition: Display the field if all fields in the form are valid.
• HasValueDisplayCondition: Display the field if the field with the given FieldId has the given Value.
• DisplayAfter: Display the field after the field with the given FieldId is visible and valid (entry finished).
• OrDisplayCondition: Display the field if any of the given Conditions are met.
• AndDisplayCondition: Display the field if all the given Conditions are met.

Available validators

• CustomValidator: Custom validator. Takes a function with the prop field any that returns (bool, error) as the Validator.
• AllFieldsVaild: Validate the field if all fields in the form are valid.
• IsValidValidator: Validate the field if the fields given in FieldIds are valid.

Message

A simple message field that can be used to display text. No user input is possible.

Text

A simple text input field.

Properties:

• Placeholder (string): Placeholder text for the input field.
• Prompt (string): Prompt text for the input field.

Available validators

• NotEmptyValidator: Validate that the field is not empty.
• MinLengthValidator: Validate that the field has a MinLength number of characters.
• MaxLengthValidator: Validate that the field has a MaxLength number of characters.
• IpValidator: Validate that the field is a valid IPv4 address.
• RegexValidator: Validate that the field matches the given RegexPattern (string).
• UrlValidator: Validate that the field is a valid URL. (matches the regex ^https?://.)

Number

A number input field that only accepts numbers.

Available validators

• MinValidator: Validate that the field is greater than or equal to Min.
• MaxValidator: Validate that the field is less than or equal to Max.
• IsIntegerValidator: Validate that the field is an integer.

MultipleChoice

A multiple choice field that allows the user to select one option from a list.

Properties:

• Options (map[string]Option): List of options to choose from.

Option has the following properties:

• Label (string): Label for the option.
• Description (string): Description for the option.

Available validators

• ChoiceValidator: Validate that the field is one of the options in Options.

FieldGroup

A group of fields that can be displayed conditionally.

Properties:

• Fields ([]Field): List of fields in the group.
• heading (string): Heading for the group.

TODOs

• Add more field types
• Add way to customize error messages (e.g., for translations)
• Add more UI frameworks for rendering (e.g., charm.sh for terminal UIs)
• Add more display conditions
• Add more validators
• Add tests
• Add more examples
• Clen up code
• Add more documentation