typescript-json-schema

Generate json-schemas from your Typescript sources.

Features

• Compiles your Typescript program to get complete type information.
• Translates required properties, extends, annotation keywords, property initializers as defaults. You can find examples for these features in the test examples.

Usage

Command line

• Install with npm install typescript-json-schema -g
• Generate schema from a typescript type: typescript-json-schema project/directory/tsconfig.json TYPE

To generate files for only some types in tsconfig.json specify filenames or globs with the --include option. This is especially useful for large projects.

In case no tsconfig.json is available for your project, you can directly specify the .ts files (this in this case we use some built-in compiler presets):

• Generate schema from a typescript type: typescript-json-schema "project/directory/**/*.ts" TYPE

The TYPE can either be a single, fully qualified type or * to generate the schema for all types.

Usage: typescript-json-schema <path-to-typescript-files-or-tsconfig> <type>

Options:
  --refs                Create shared ref definitions.                               [boolean] [default: true]
  --aliasRefs           Create shared ref definitions for the type aliases.          [boolean] [default: false]
  --topRef              Create a top-level ref definition.                           [boolean] [default: false]
  --titles              Creates titles in the output schema.                         [boolean] [default: false]
  --defaultProps        Create default properties definitions.                       [boolean] [default: false]
  --noExtraProps        Disable additional properties in objects by default.         [boolean] [default: false]
  --propOrder           Create property order definitions.                           [boolean] [default: false]
  --required            Create required array for non-optional properties.           [boolean] [default: false]
  --strictNullChecks    Make values non-nullable by default.                         [boolean] [default: false]
  --useTypeOfKeyword    Use `typeOf` keyword (https://goo.gl/DC6sni) for functions.  [boolean] [default: false]
  --out, -o             The output file, defaults to using stdout
  --validationKeywords  Provide additional validation keywords to include            [array]   [default: []]
  --include             Further limit tsconfig to include only matching files        [array]   [default: []]
  --ignoreErrors        Generate even if the program has errors.                     [boolean] [default: false]
  --excludePrivate      Exclude private members from the schema                      [boolean] [default: false]
  --uniqueNames         Use unique names for type symbols.                           [boolean] [default: false]
  --rejectDateType      Rejects Date fields in type definitions.                     [boolean] [default: false]
  --id                  Set schema id.                                               [string] [default: ""]

Programmatic use

import {resolve} from "path";

import * as TJS from "typescript-json-schema";

// optionally pass argument to schema generator
const settings: TJS.PartialArgs = {
    required: true
};

// optionally pass ts compiler options
const compilerOptions: TJS.CompilerOptions = {
    strictNullChecks: true
}

// optionally pass a base path
const basePath = "./my-dir";

const program = TJS.getProgramFromFiles([resolve("my-file.ts")], compilerOptions, basePath);

// We can either get the schema for one file and one type...
const schema = TJS.generateSchema(program, "MyType", settings);


// ... or a generator that lets us incrementally get more schemas

const generator = TJS.buildGenerator(program, settings);

// all symbols
const symbols = generator.getUserSymbols();

// Get symbols for different types from generator.
generator.getSchemaForSymbol("MyType");
generator.getSchemaForSymbol("AnotherType");

// In larger projects type names may not be unique,
// while unique names may be enabled.
const settings: TJS.PartialArgs = {
    uniqueNames: true
};

const generator = TJS.buildGenerator(program, settings);

// A list of all types of a given name can then be retrieved.
const symbolList = generator.getSymbols("MyType");

// Choose the appropriate type, and continue with the symbol's unique name.
generator.getSchemaForSymbol(symbolList[1].name);

// Also it is possible to get a list of all symbols.
const fullSymbolList = generator.getSymbols();

getSymbols('<SymbolName>') and getSymbols() return an array of SymbolRef, which is of the following format:

type SymbolRef = {
  name: string;
  typeName: string;
  fullyQualifiedName: string;
  symbol: ts.Symbol;
};

getUserSymbols and getMainFileSymbols return an array of string.

Annotations

The schema generator converts annotations to JSON schema properties.

For example

export interface Shape {
    /**
     * The size of the shape.
     *
     * @minimum 0
     * @TJS-type integer
     */
    size: number;
}

will be translated to

{
    "$ref": "#/definitions/Shape",
    "$schema": "http://json-schema.org/draft-07/schema#",
    "definitions": {
        "Shape": {
            "properties": {
                "size": {
                    "description": "The size of the shape.",
                    "minimum": 0,
                    "type": "integer"
                }
            },
            "type": "object"
        }
    }
}

Note that we needed to use @TJS-type instead of just @type because of an issue with the typescript compiler.

Background

Inspired and builds upon Typson, but typescript-json-schema is compatible with more recent Typescript versions. Also, since it uses the Typescript compiler internally, more advanced scenarios are possible.

Debugging

npm run debug -- test/programs/type-alias-single/main.ts --aliasRefs true MyString

And connect via the debugger protocol.