@fogpipe/forma-core

Core runtime for Forma - a declarative form specification with FEEL expressions for dynamic behavior.

Installation

``bash
npm install @fogpipe/forma-core
`

Features

- Type Definitions - Complete TypeScript types for Forma specifications
- FEEL Evaluation - Evaluate FEEL expressions in form context
- Visibility Engine - Determine which fields should be visible
- Required Engine - Evaluate conditional required state
- Enabled Engine - Evaluate conditional enabled/disabled state
- Calculation Engine - Compute derived field values
- Validation Engine - Validate form data against rules

Usage

$3

`typescript
import type { Forma } from '@fogpipe/forma-core';

const form: Forma = {
meta: {
title: "Contact Form"
},
fields: [
{
id: "name",
type: "text",
label: "Full Name",
required: true
},
{
id: "email",
type: "email",
label: "Email",
required: true
},
{
id: "phone",
type: "text",
label: "Phone Number",
// Only required if email is not provided
required: "email = null or email = \"\""
}
]
};
`

$3

`typescript
import {
getVisibility,
getRequired,
getEnabled,
validate,
calculate
} from '@fogpipe/forma-core';

const data = { name: "John", email: "john@example.com" };

// Get visibility state for all fields
const visibility = getVisibility(data, form);

// Get required state for all fields
const required = getRequired(data, form);

// Get enabled state for all fields
const enabled = getEnabled(data, form);

// Validate form data
const result = validate(data, form);
if (!result.valid) {
console.log('Errors:', result.errors);
}

// Calculate computed values
const computed = calculate(data, form);
`

$3

`typescript
import { evaluate, evaluateBoolean } from '@fogpipe/forma-core/feel';

const context = {
data: { age: 25, country: "US" }
};

// Evaluate any expression
const result = evaluate("age * 2", context);
if (result.success) {
console.log(result.value); // 50
}

// Evaluate boolean expression
const isAdult = evaluateBoolean("age >= 18", context); // true
`

API Reference

$3

- Forma - Complete form specification
- FieldDefinition - Field definition
- ComputedField - Computed field definition
- PageDefinition - Page definition for wizards
- FieldError - Validation error
- ValidationResult - Validation result

$3

#### Visibility

`typescript
getVisibility(data, spec, options?) → Record
isFieldVisible(fieldId, data, spec, options?) → boolean
getPageVisibility(data, spec, options?) → Record
`

#### Required

`typescript
getRequired(data, spec, options?) → Record
isRequired(fieldId, data, spec, options?) → boolean
`

#### Enabled

`typescript
getEnabled(data, spec, options?) → Record
isEnabled(fieldId, data, spec, options?) → boolean
`

#### Validation

`typescript
validate(data, spec, options?) → ValidationResult
validateSingleField(fieldId, value, data, spec, options?) → FieldError[]
`

#### Calculation

`typescript
calculate(data, spec, options?) → Record
calculateWithErrors(data, spec, options?) → CalculationResult
calculateField(fieldName, data, spec, existingComputed?, options?) → unknown
`

$3

`typescript
evaluate(expression, context) → EvaluationOutcome
evaluateBoolean(expression, context) → boolean
evaluateNumber(expression, context) → number | null
evaluateString(expression, context) → string | null
isValidExpression(expression) → boolean
``

License

MIT