Shapeshifter is a command line tool for generating ECMAScript (ES) compatible files that export PropTypes, Flow aliases, or TypeScript interfaces, as well as relation schema classes from JSON or GraphQL schematic files. Schematics can represent database tables, API endpoints, data structures, resources, internal shapes, and more.

Take this user schematic for example.

"name": "User",
"attributes": {
"id": "number",
"username": "string",
"email": {
"type": "string",
"nullable": true
"location": {
"type": "shape",
"optional": true,
"attributes": {
"lat": "number",
"long": "number"

Which transpiles down to the following PropTypes.

import PropTypes from 'prop-types';
export const UserShape = PropTypes.shape({
id: PropTypes.number.isRequired,
username: PropTypes.string.isRequired,
email: PropTypes.string,
location: PropTypes.shape({
lat: PropTypes.number.isRequired,
long: PropTypes.number.isRequired,

Or the following Flow aliases.

/* @flow */
export type UserType = {
id: number,
username: string,
email: ?string,
location?: {
lat: number,
long: number,

Or TypeScript interfaces.

export interface UserInterface {
id: number;
username: string;
email: string | null;
location?: {
lat: number,
long: number,

And finally, the schema class. Which can define ORM styled relations.

export const userSchema = new Schema('users', 'id');


  • Node 4+

  • PropTypes 15+ / Flow 0.60+ / TypeScript 2.4+

  • IE 10+


Shapeshifter can be used as a dev dependency if you're only generating type definitions (shapes, aliases, interfaces, etc).

yarn add shapeshifter --dev
// Or
npm install shapeshifter --save-dev

If you're generating schema classes, it will need to be a normal dependency.

yarn add shapeshifter
// Or
npm install shapeshifter --save


By default, Shapeshifter will parse .json or .js files. It can parse the following file types by installing additional dependencies.


Shapeshifter is provided as a binary which can be executed and piped like so.

shapeshifter [options] <input> > <output>

The binary input accepts either a single schematic file, a directory of schematic files, or multiple files. If a directory is provided, they will be combined into a single output.

By default, the binary will send output to stdout, which can then be redirected to a destination of your choosing, otherwise the output will be sent to the console.


  • --attributes (bool) - Include an attribute list in the schema class export. Defaults to "false".

  • --definitions (bool) - Include type annotations and definitions in the output. Defaults to


  • --disable-eslint (bool) - Prepend an eslint-disable comment to the top of the output. Defaults

    to "false".

  • --[no-]enums (bool) - Toggle between enums and unions. Defaults to "true". (TypeScript only)

  • --flow (bool) - Generate Flow definitions. Defaults to "false".

  • --indent (string) - Defines the indentation characters to use in the generated output. Defaults

    to 2 spaces.

  • --infer-prop-types-shape (bool) - When both prop-types and typescript definitions are used,

    the TypeScript interface can be named to match the PropTypes shape, allowing for automatic type

    inference. Defaults to "false". (TypeScript and Flow only)

  • --import (string) - The import path to a Schema class, inserted at the top of every output

    file. Defaults to "shapeshifter".

  • --nullable (bool) - Marks all attributes as nullable by default. Not applicable to GraphQL.

    Defaults to false.

  • --optional (bool) - Marks all attributes as optional by default. Not applicable to GraphQL.

    Defaults to false.

  • --prop-types (bool) - Generate PropTypes definitions. Defaults to "false".

  • --schemas (bool) - Include schema class exports in the output. Defaults to "false".

  • --schema-generics (bool) - Explicity type generic callsites for schemas. Defaults to "false".

    (TypeScript only)

  • --strip-prop-types (bool) - Wrap PropType definitions in process.env.NODE_ENV production

    expressions, allowing them to be removed with dead code elimination.

  • --[no-]suffix (bool) - Toggle definition name suffixes. Be careful when using this with multiple

    renderers. Defaults to "true".

  • --typescript (bool) - Generate TypeScript definitions. Defaults to "false".

  • --use-define (bool) - Update all schema relations to use Schema#define.