jsonschema-ts-type

jsonschema-ts-type

This package provide a helper Type Schema which will covert the JSONSchema type into TypeScript type. Note the JSONSchema must be literal typed to make this helper Type Schema to be able to parse the Schema correctly, the JSONSchema must stay in .ts file and followed as const instead of .json file since the .json file will result in generic types like string or number.

Difference compared to json-schema-to-typescript?

This package have no running code! It's just a TypeScript generic type which will convert the JSONSchema from literal typed JSON to a TypeScript type. By using json-schema-to-typescript, The JSONSchema is converted to .d.ts from CLI or programmatically way, by using this package, the JSONSchema definitions stay in the .ts file and the type is converted by TypeScript generic typing system.

Should I use this one instead of json-schema-to-typescript?

If you have been using json-schema-to-typescript in your project already, you should continue use it since it's much more reliable. If it's new to your project you may try this one, but use it at your own risk, it may be broken on complex JSONSchema since it costs too much for the TypeScript compiler. Again, json-schema-to-typescript is more reliable.

How to use

This package can be used like this:

import {Schema} from 'jsonschema-ts-type';

const schemaObj = {
  description: 'Any validation failures are shown in the right-hand Messages pane.',
  type: 'object',
  properties: {
    foo: {
      type: 'number',
    },
    bar: {
      type: 'string',
      enum: ['a', 'b', 'c'],
    },
  },
  additionalProperties: false,
} as const; // Note: `as const` is required to turn the type into literal type

type TypeObj = Schema<typeof schemaObj>;
// The TypeObj will be {foo?: number; bar?: "a" | "b" | "c"}

Which JSONSchema features are supported

The following features of JSONSchema are supported to be converted into TypeScript Type:

• Primitive type (not the limitation like minium, pattern cannot be applied).
• Array Type (both generic array and Tuple, but contains, minItems, maxItems and uniqueItems are not supported)
• Object Type (patternProperties are not supported, additionalProperties cannot be parsed to specific type, name, size and dependencies are also not supported)
• Enumerated values and constant value
• anyOf combination keyword, note allOf, oneOf and not are not supported
• $ref, note only absolute path is supported, URI pattern ("definitions.json#/address") and id based location ("$ref": "#address") are not supported

Contribution

Clone this repo and open it with VSCode, everything should be working properly. Please add the generic type in src folder and add related test cases in test folder.