JSON Schema Gen

A very simplified generation of 2020-12 JSON Schemas using an example JSON object to start with. I hope to never have external dependencies; we'll see how that goes.

Limitations (currently)

I know right, let me roast my own tool right off the bat. That'll show 'em

• None of the schema composition keywords are supported. This would be things like allOf, anyOf, and oneOf.
• Type constraints are not generated. This would be things like minLength or pattern for strings or minimum for numbers or additionalProperties for objects. It's only the type that this tool generates currently.
• Arrays are not scanned exhaustively; instead, only the first element of any array is inspected for a type to use under the items field. If that type is primitive (string, number, boolean, or null), then items will use a contains field with that type. This also means tuples are not supported.

Things It Does Do

If I haven't steered you away with my glowing review in the section above, here is the same information from a more positive perspective.

• Traverses your entire object recursively, even into arrays and objects within arrays
• Arrays as direct children of arrays are supported
• Has no options argument, so you don't have to worry about what to pass to the function

Usage

import { genSchema } from 'json_schema_gen';
// OR
const { genSchema } = require('json_schema_gen');

const testObject = {
  field: 'value',
  innerObj: {
    innerField: 420,
  },
  myList: [1, 2, 3],
  myList2: ['a', 'b', 'c'],
  underObj: {
    oneMoreList: [{ type: 'something ' }],
  },
  arrInArr: [
    ['tup1', 'tup2'],
    ['val1', 'val2'],
  ],
};

const resultSchema = genSchema(testObject);
console.log(JSON.stringify(resultSchema, null, 2));