ts-json-schema-generator
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Generate JSON schema from your Typescript sources
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# ts-json-schema-generator
[](https://codecov.io/gh/vega/ts-json-schema-generator)
[](https://www.npmjs.com/package/ts-json-schema-generator)
Extended version of [https://github.com/xiag-ag/typescript-to-json-schema](https://github.com/xiag-ag/typescript-to-json-schema).
Inspired by [`YousefED/typescript-json-schema`](https://github.com/YousefED/typescript-json-schema). Here's the differences list:
- this implementation avoids the use of `typeChecker.getTypeAtLocation()` (so probably it keeps correct type aliases)
- processing AST and formatting JSON schema have been split into two independent steps
- not exported types, interfaces, enums are not exposed in the `definitions` section in the JSON schema
## Contributors
This project is made possible by a [community of contributors](https://github.com/vega/ts-json-schema-generator/graphs/contributors). We welcome contributions of any kind (issues, code, documentation, examples, tests,...). Please read our [code of conduct](https://vega.github.io/vega/about/code-of-conduct).
## CLI Usage
Run the schema generator with npx:
```bash
npx ts-json-schema-generator --path 'my/project/**/*.ts' --type 'My.Type.Name'
```
Or install the package and then run it
```bash
npm install --save ts-json-schema-generator
./node_modules/.bin/ts-json-schema-generator --path 'my/project/**/*.ts' --type 'My.Type.Name'
```
Note that different platforms (e.g. Windows) may use different path separators so you may have to adjust the command above.
Also note that you need to quote paths with `*` as otherwise the shell will expand the paths and therefore only pass the first path to the generator.
By default, the command-line generator will use the `tsconfig.json` file in the current working directory, or the first parent directory that contains a `tsconfig.json` file up to the root of the filesystem. If you want to use a different `tsconfig.json` file, you can use the `--tsconfig` option. In particular, if you need to use different compilation options for types, you may want to create a separate `tsconfig.json` file for the schema generation only.
### Options
```
-p, --path <path> Source file path
-t, --type <name> Type name
-i, --id <name> $id for generated schema
-f, --tsconfig <path> Custom tsconfig.json path
-e, --expose <expose> Type exposing (choices: "all", "none", "export", default: "export")
-j, --jsDoc <extended> Read JsDoc annotations (choices: "none", "basic", "extended", default: "extended")
--markdown-description Generate `markdownDescription` in addition to `description`.
--functions <functions> How to handle functions. `fail` will throw an error. `comment` will add a comment. `hide` will treat the function like a NeverType or HiddenType.
(choices: "fail", "comment", "hide", default: "comment")
--minify Minify generated schema (default: false)
--unstable Do not sort properties
--strict-tuples Do not allow additional items on tuples
--no-top-ref Do not create a top-level $ref definition
--no-type-check Skip type checks to improve performance
--no-ref-encode Do not encode references
-o, --out <file> Set the output file (default: stdout)
--validation-keywords [value] Provide additional validation keywords to include (default: [])
--additional-properties Allow additional properties for objects with no index signature (default: false)
-V, --version output the version number
-h, --help display help for command
```
## Programmatic Usage
```js
// main.js
const tsj = require("ts-json-schema-generator");
const fs = require("fs");
/** @type {import('ts-json-schema-generator/dist/src/Config').Config} */
const config = {
path: "path/to/source/file",
tsconfig: "path/to/tsconfig.json",
type: "*", // Or <type-name> if you want to generate schema for that one type only
};
const outputPath = "path/to/output/file";
const schema = tsj.createGenerator(config).createSchema(config.type);
const schemaString = JSON.stringify(schema, null, 2);
fs.writeFile(outputPath, schemaString, (err) => {
if (err) throw err;
});
```
Run the schema generator via `node main.js`.
### Custom formatting
Extending the built-in formatting is possible by creating a custom formatter and adding it to the main formatter:
1. First we create a formatter, in this case for formatting function types (note that there is a built in one):
```ts
// my-function-formatter.ts
import { BaseType, Definition, FunctionType, SubTypeFormatter } from "ts-json-schema-generator";
import ts from "typescript";
export class MyFunctionTypeFormatter implements SubTypeFormatter {
// You can skip this line if you don't need childTypeFormatter
public constructor(private childTypeFormatter: TypeFormatter) {}
public supportsType(type: BaseType): boolean {
return type instanceof FunctionType;
}
public getDefinition(type: FunctionType): Definition {
// Return a custom schema for the function property.
return {
type: "object",
properties: {
isFunction: {
type: "boolean",
const: true,
},
},
};
}
// If this type does NOT HAVE children, generally all you need is:
public getChildren(type: FunctionType): BaseType[] {
return [];
}
// However, if children ARE supported, you'll need something similar to
// this (see src/TypeFormatter/{Array,Definition,etc}.ts for some examples):
public getChildren(type: FunctionType): BaseType[] {
return this.childTypeFormatter.getChildren(type.getType());
}
}
```
2. Then we add the formatter as a child to the core formatter using the augmentation callback:
```ts
import { createProgram, createParser, SchemaGenerator, createFormatter } from "ts-json-schema-generator";
import { MyFunctionTypeFormatter } from "./my-function-formatter.ts";
import fs from "fs";
const config = {
path: "path/to/source/file",
tsconfig: "path/to/tsconfig.json",
type: "*", // Or <type-name> if you want to generate schema for that one type only
};
// We configure the formatter an add our custom formatter to it.
const formatter = createFormatter(config, (fmt, circularReferenceTypeFormatter) => {
// If your formatter DOES NOT support children, e.g. getChildren() { return [] }:
fmt.addTypeFormatter(new MyFunctionTypeFormatter());
// If your formatter DOES support children, you'll need this reference too:
fmt.addTypeFormatter(new MyFunctionTypeFormatter(circularReferenceTypeFormatter));
});
const program = createProgram(config);
const parser = createParser(program, config);
const generator = new SchemaGenerator(program, parser, formatter, config);
const schema = generator.createSchema(config.type);
const outputPath = "path/to/output/file";
const schemaString = JSON.stringify(schema, null, 2);
fs.writeFile(outputPath, schemaString, (err) => {
if (err) throw err;
});
```
### Custom parsing
Similar to custom formatting, extending the built-in parsing works practically the same way:
1. First we create a parser, in this case for parsing construct types:
```ts
// my-constructor-parser.ts
import { Context, StringType, ReferenceType, BaseType, SubNodeParser } from "ts-json-schema-generator";
// use typescript exported by TJS to avoid version conflict
import ts from "ts-json-schema-generator";
export class MyConstructorParser implements SubNodeParser {
supportsNode(node: ts.Node): boolean {
return node.kind === ts.SyntaxKind.ConstructorType;
}
createType(node: ts.Node, context: Context, reference?: ReferenceType): BaseType | undefined {
return new StringType(); // Treat constructors as strings in this example
}
}
```
2. Then we add the parser as a child to the core parser using the augmentation callback:
```ts
import { createProgram, createParser, SchemaGenerator, createFormatter } from "ts-json-schema-generator";
import { MyConstructorParser } from "./my-constructor-parser.ts";
import fs from "fs";
const config = {
path: "path/to/source/file",
tsconfig: "path/to/tsconfig.json",
type: "*", // Or <type-name> if you want to generate schema for that one type only
};
const program = createProgram(config);
// We configure the parser an add our custom parser to it.
const parser = createParser(program, config, (prs) => {
prs.addNodeParser(new MyConstructorParser());
});
const formatter = createFormatter(config);
const generator = new SchemaGenerator(program, parser, formatter, config);
const schema = generator.createSchema(config.type);
const outputPath = "path/to/output/file";
const schemaString = JSON.stringify(schema, null, 2);
fs.writeFile(outputPath, schemaString, (err) => {
if (err) throw err;
});
```
## Current state
- `interface` types
- `enum` types
- `union`, `tuple`, `type[]` types
- `Date`, `RegExp`, `URL` types
- `string`, `boolean`, `number` types
- `"value"`, `123`, `true`, `false`, `null`, `undefined` literals
- type aliases
- generics
- `typeof`
- `keyof`
- conditional types
- functions
- `Promise<T>` unwraps to `T`
- Overrides (like ``)
## Run locally
`npm run --silent run -- --path 'test/valid-data/type-mapped-array/*.ts' --type 'MyObject'`
## Debug
`npm run --silent debug -- --path 'test/valid-data/type-mapped-array/*.ts' --type 'MyObject'`
And connect via the debugger protocol.
[AST Explorer](https://astexplorer.net/) is amazing for developers of this tool!
## Publish
Publishing is handled by a 2-branch [pre-release process](https://intuit.github.io/auto/docs/generated/shipit#next-branch-default), configured in `publish-auto.yml`. All changes should be based off the default `next` branch, and are published automatically.
- PRs made into the default branch are auto-deployed to the `next` pre-release tag on NPM. The result can be installed with `npm install ts-json-schema-generator@next`
- When merging into `next`, please use the `squash and merge` strategy.
- To release a new stable version, open a PR from `next` into `stable` using this [compare link](https://github.com/vega/ts-json-schema-generator/compare/stable...next).
- When merging from `next` into `stable`, please use the `create a merge commit` strategy.