JSONForms Provider Protocols

A Vue 3 library that adds dynamic data provider capabilities to JSONForms, enabling form fields to fetch and display data from various sources like REST APIs, databases, and custom protocols.

✨ Features

• 🔌 Protocol-based Architecture: Extensible system for different data sources
• 🚀 Vue 3 Integration: Seamless integration with JSONForms Vue renderers
• 💾 Built-in Caching: TTL-based caching with configurable expiration
• 🔄 Dynamic Data Loading: Support for mount, focus, and query-based loading
• 🎯 Template Support: Dynamic URL and parameter templating
• 📦 TypeScript Support: Full TypeScript definitions included
• 🔐 Authentication: Flexible authentication mechanism support

📦 Installation

# Using bun (recommended)
bun add @narrative.io/jsonforms-provider-protocols

# Using npm  
npm install @narrative.io/jsonforms-provider-protocols

# Peer dependencies
bun add @jsonforms/vue @jsonforms/core vue

🚀 Quick Start

1. Register the Plugin

import { createApp } from 'vue'
import ProviderProtocols, { RestApiProtocol } from '@narrative.io/jsonforms-provider-protocols'

const app = createApp(App)

app.use(ProviderProtocols, {
  protocols: [RestApiProtocol()]
})

2. Configure Your Form

{
  "type": "Control",
  "scope": "#/properties/country",
  "options": {
    "provider": {
      "ref": "countries",
      "protocol": "rest_api", 
      "config": {
        "url": "https://api.example.com/countries",
        "items": "$.data[*]",
        "map": {
          "label": "$.name",
          "value": "$.code"
        }
      }
    }
  }
}

3. Use in Vue

<script setup lang="ts">
import { JsonForms } from '@jsonforms/vue'
import { providerRenderers } from '@narrative.io/jsonforms-provider-protocols/vue'
import { markRaw, ref } from 'vue'

const data = ref({ country: null })
const handleChange = (event) => data.value = event.data
</script>

<template>
  <JsonForms
    :data="data"
    :schema="schema"
    :uischema="uischema"
    :renderers="markRaw(providerRenderers)"
    @change="handleChange"
  />
</template>

📖 Documentation

Getting Started

• Installation & Setup
• Basic Examples

Core Concepts

• Protocols - How to fetch and transform data
• Authentication - Configure and use authentication
• Vue Components - Available components and composables
• API Reference - Complete API documentation

Examples

• Simple Dropdown
• Cascading Dropdowns
• Autocomplete Search
• Custom Protocols
• Custom Renderers
• More Examples

Help & Troubleshooting

• Troubleshooting Guide
• GitHub Issues

🔧 Key Concepts

Protocols

Define how data is fetched and transformed:

const CustomProtocol: Protocol = {
  protocol: 'my-api',
  async resolve(config, context) {
    const response = await fetch(config.url)
    const data = await response.json()
    
    return {
      items: data.map(item => ({
        label: item.name,
        value: item.id
      })),
      ttl: 300
    }
  }
}

Data Transforms

Transform API response data before mapping to form items using a pipeline of transforms:

{
  "provider": {
    "protocol": "rest_api",
    "config": {
      "url": "https://api.example.com/data",
      "items": "$.data[*]",
      "transforms": [
        {
          "name": "flatten",
          "key": "children",
          "labelFormat": "{parent.name} → {name}"
        },
        {
          "name": "filter",
          "key": "active",
          "values": [true]
        }
      ],
      "map": {
        "label": "$.name",
        "value": "$.id"
      }
    }
  }
}

Built-in Transforms

Flatten Transform Recursively flattens nested tree structures into a single-level array:

{
  "name": "flatten",
  "key": "children",
  "labelFormat": "{parent.name} → {name}"
}

• key: The property containing nested children arrays
• labelFormat (optional): Template for formatting labels using parent and child properties
• Adds _depth, _parent, and _formattedLabel metadata to items

Filter Transform Filters items based on property values:

{
  "name": "filter",
  "key": "category",
  "values": ["A", "B"]
}

• key: The property to check
• values (optional): Array of values to match. If omitted, filters by key existence

Combining Transforms Transforms are applied sequentially in pipeline order:

{
  "transforms": [
    { "name": "flatten", "key": "children" },
    { "name": "filter", "key": "type", "values": ["product"] }
  ]
}

Custom Transforms Register custom transforms for your specific needs:

import { registerTransform } from '@narrative.io/jsonforms-provider-protocols'

registerTransform('uppercase', (items, config) => {
  return items.map(item => ({
    ...item,
    name: item.name.toUpperCase()
  }))
})

Template Variables

Create dynamic URLs using form data:

{
  "url": "https://api.example.com/countries/{{data.country}}/states",
  "query": { "search": "{{ui.query}}" }
}

Load Strategies

Control when data is fetched:

• mount - Load when component mounts (default)
• onFocus - Load when field receives focus
• query - Load when user types (autocomplete)

Derive Functionality

Auto-populate fields from form data or external sources:

{
  "type": "Control",
  "scope": "#/properties/derived_field",
  "options": {
    "derive": "country",
    "mode": "follow",
    "readonly": true
  }
}

External Data Support

Access external data sources separate from form data using the externalData() syntax:

<script setup>
// Provide external data to the form
const externalData = ref({
  user: { preferences: { theme: "dark" } },
  tree: { name: "Oak", type: "Deciduous" }
})

provide('externalData', externalData)
</script>

{
  "type": "Control", 
  "scope": "#/properties/tree_preference",
  "options": {
    "derive": "externalData(tree.name)",
    "mode": "follow",
    "readonly": true
  }
}

Error Handling

Control error display behavior with the showError property:

{
  "provider": {
    "protocol": "rest_api",
    "config": {
      "url": "https://api.example.com/data",
      "showError": false,
      "items": "$.data[*]",
      "map": { "label": "$.name", "value": "$.id" }
    }
  }
}

When showError is false, failed requests return empty results instead of throwing errors. Defaults to true.

Composables

Use providers directly in your components:

<script setup>
import { useProvider } from '@narrative.io/jsonforms-provider-protocols/vue'

const { items, loading, error, reload } = useProvider(binding, context)
</script>

🛠 Development

# Install dependencies
bun install

# Run tests
bun test

# Build library  
bun run build

# Type checking
bunx vue-tsc --noEmit

🤝 Contributing

Contributions are welcome! Please read our Contributing Guide and check out the issue tracker.

📄 License

MIT - see LICENSE file for details.

🆘 Support

• Documentation
• GitHub Issues
• Troubleshooting Guide