json-schema-deriver v1.0.7

JSON-Schema-Deriver

Derives JSON-Schema from a given JSON Sample

Table of Contents

• Motivation
• Installation
• Usage
• Derive JSON Schema from sample JSON
• Known limitations
• Sample Data

Motivation

This tool allows to derive a JSON schema from any given JSON object. It allows you to quickly specify JSON schemas using sample data as a baseline for a schema specification.

Installation

npm install json-schema-deriver

Usage

Using a given JS Object

let obj = {
  name: "json-schema-deriver",
  version: "1.0.6",
  description: "",
  main: "build/app.js",
  directories: {
    build: "build",
  },
  repository: {
    type: "git",
    url: "https://github.com/geopackix/json-schema-deriver",
  },
  scripts: {
    build: "tsc --build",
    start: "tsc --build && node ./build/example/createSchemaFromJSON.js",
  },
  author: "Geopackix (https://github.com/geopackix)",
  license: "MIT",
  devDependencies: {
    typescript: "^4.1.3",
  },
  keywords: ["json", "json-schema", "schema", "deriver"],
};

Synchronous

const Schema = require('json-schema-deriver');

[...]

let jsonSchema = await Schema.deriveSchema(obj,'Package.json Schema');
console.log(jsonSchema)

Asynchronous

let jsonSchema = Schema.deriveSchema(obj, "Package.json Schema").then(
  (schema) => {
    console.log(schema);
  }
);

Derive JSON Schema from sample JSON

Run the following command to derive JSON schema from input JSON file.

node createSchemaFromJSON.js <sample file.json>

Example

node .\build\example\createSchemaFromJSON.js .\sampleFiles\sampleBattery.json

Known limitations

• Arrays in multi dimentional arrays lead to undefined-element definition.

Sample Data

JSON

{
  "$schema":"./sample.schema.json",
  "name":"SchemaDeriverName",
  "numberProp" : 18.5,
  "NumberArray": [1,2,3,4],
  "ObjectArray":[
    {
      "ObjectId":"7B3",
      "InnerObjectArray":[
        {
          "name":"TestName",
          "property1" : "18.5"

        }
      ],
      "InnerStringArray":["1","2","3"]
    },
    {
      "ObjectId":"7B3"
    }
  ]
}

Derived JSON-Schema

{
  "description": "Auto-Generated JSON Schema for JSON File using json-schema-deriver (https://github.com/geopackix/json-schema-deriver)",
  "title": "JSON File",
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "$schema": {
      "type": "string",
      "description": "Description of $schema",
      "examples": [
        "./sample.schema.json"
      ]
    },
    "name": {
      "type": "string",
      "description": "Description of name",
      "examples": [
        "SchemaDeriverName"
      ]
    },
    "numberProp": {
      "type": "number",
      "description": "Description of numberProp",
      "examples": [
        18.5
      ]
    },
    "NumberArray": {
      "type": "array",
      "description": "Description of NumberArray",
      "items": {
        "type": "number"
      }
    },
    "ObjectArray": {
      "type": "array",
      "description": "Description of ObjectArray",
      "items": {
        "$ref": "#/definitions/ObjectArray-element"
      }
    }
  },
  "definitions": {
    "InnerObjectArray-element": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string",
          "description": "Description of name",
          "examples": [
            "TestName"
          ]
        },
        "property1": {
          "type": "string",
          "description": "Description of property1",
          "examples": [
            "18.5"
          ]
        }
      },
      "additionalProperties": false
    },
    "ObjectArray-element": {
      "type": "object",
      "properties": {
        "ObjectId": {
          "type": "string",
          "description": "Description of ObjectId",
          "examples": [
            "7B3"
          ]
        },
        "InnerObjectArray": {
          "type": "array",
          "description": "Description of InnerObjectArray",
          "items": {
            "$ref": "#/definitions/InnerObjectArray-element"
          }
        },
        "InnerStringArray": {
          "type": "array",
          "description": "Description of InnerStringArray",
          "items": {
            "type": "string"
          }
        }
      },
      "additionalProperties": false
    }
  }
}