FormKit

Declarative form builder with validation rules, result builder DSL, and dynamic JSON forms

Requirements

• Swift >= 6.0
• macOS 13+ / iOS 16+ / tvOS 16+ / watchOS 9+

Installation

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/philiprehberger/swift-form-kit.git", from: "0.1.0")
]

Then add "FormKit" to your target dependencies:

.target(name: "YourTarget", dependencies: [
    .product(name: "FormKit", package: "swift-form-kit")
])

Usage

import FormKit

// Build a form with the DSL
let section = FormSection(title: "Profile") {
    FormTextField(id: "name", label: "Full Name", validation: [.required()])
    FormTextField(id: "email", label: "Email", validation: [.required(), .email()])
    FormNumberField(id: "age", label: "Age", validation: [.range(18...120)])
    FormToggleField(id: "newsletter", label: "Subscribe to newsletter")
}

let model = FormModel(sections: [section])

Validation

// Built-in rules
FormTextField(id: "password", label: "Password", validation: [
    .required(),
    .minLength(8),
    .maxLength(100),
    .pattern(".*[A-Z].*", message: "Must contain an uppercase letter")
])

// Custom rule
FormTextField(id: "username", label: "Username", validation: [
    .custom(message: "Must start with a letter") { value in
        guard let str = value as? String else { return false }
        return str.first?.isLetter ?? false
    }
])

// Validate all fields
let isValid = model.validate()
let errors = model.errors  // ["password": ["Must be at least 8 characters"]]

Dynamic Forms from JSON

let json = """
[{"title": "Contact", "fields": [
    {"id": "name", "type": "text", "label": "Name", "required": true},
    {"id": "age", "type": "number", "label": "Age"}
]}]
""".data(using: .utf8)!

let sections = try DynamicForm.from(json: json)
let model = FormModel(sections: sections)

SwiftUI Rendering

struct ProfileForm: View {
    @State private var model = FormModel(sections: profileSections)

    var body: some View {
        FormView(model: model)
        Button("Submit") { if model.validate() { submit() } }
            .disabled(!model.isValid)
    }
}

API

FormModel

Property/Method	Description
values	Current form values keyed by field ID
errors	Validation errors keyed by field ID
isValid	Whether all fields pass validation
setValue(_:for:)	Set a value for a field
validate()	Validate all fields
validate(fieldId:)	Validate a single field
reset()	Reset form to initial values

ValidationRule

Static Method	Description
.required()	Field must not be empty
.minLength(_:)	Minimum string length
.maxLength(_:)	Maximum string length
.pattern(_:message:)	Regex pattern match
.email()	Valid email format
.range(_:)	Number within range
.custom(message:_:)	Custom validation closure

Field Types

Type	Description
FormTextField	Text input field
FormNumberField	Numeric input field
FormToggleField	Boolean toggle
FormPickerField	Selection from options
FormDateField	Date picker

Development

swift build
swift test

Support

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License

MIT