typed-snapshot

Generate typed TypeScript snapshots to disk — as a constant, an enum, a union type, an as const object, or an interface — with optional import type headers and timestamps.

Install

npm i typed-snapshot

or in a monorepo, add as a local workspace and npm run build inside the package.

Usage

import { writeTypedVariableToFile } from 'typed-snapshot';

await writeTypedVariableToFile({
  type: '{ base: Tokens; total: number }',
  data: { base: 'USDT', total: 123.4567 },
  variableName: 'PORTFOLIO_SALDO',
  outputPath: './data/portfolio_saldo.ts',
  importPath: '../src/enums/Tokens',
  importTypeName: 'Tokens',
  includeTimestamp: true,
});

Arrays → enum

await writeTypedVariableToFile({
  type: 'never', // ignored for enum emission
  data: ['BTC', 'ETH', 'USDT'],
  variableName: 'Token',
  outputPath: './data/Token.ts',
  typeFormat: 'enum',
});

Arrays → union type

await writeTypedVariableToFile({
  type: 'never', // ignored for type emission
  data: ['BTCUSDT', 'ETHUSDT'],
  variableName: 'Symbol',
  outputPath: './data/Symbol.ts',
  typeFormat: 'type',
});

Arrays → as const object

await writeTypedVariableToFile({
  type: 'never', // ignored for asconst emission
  data: ['BNB', 'BTC', 'USDT', 'ETH'],
  variableName: 'Token',
  outputPath: './data/Token.ts',
  typeFormat: 'asconst',
});

Generates:

export const Token = {
  BNB: 'BNB',
  BTC: 'BTC',
  USDT: 'USDT',
  ETH: 'ETH',
} as const;

Arrays → interface

await writeTypedVariableToFile({
  type: 'never', // ignored for interface emission
  data: ['BNB', 'BTC', 'USDT', 'ETH'],
  variableName: 'TokenData',
  outputPath: './data/TokenData.ts',
  typeFormat: 'interface',
});

Generates:

export interface TokenData {
  BNB: 'BNB';
  BTC: 'BTC';
  USDT: 'USDT';
  ETH: 'ETH';
}

API

• writeTypedVariableToFile(options): Promise<void>
  • type: string — type annotation for the exported const (plain mode)
  • data: any — data to serialize
  • variableName: string — export name (also used as enum/type name)
  • outputPath: string — file path to write
  • importPath?, importTypeName? — optional import type header
  • includeTimestamp? (default true)
  • typeFormat?: 'plain' | 'enum' | 'type' | 'asconst' | 'interface'

Helpers are also exported: generateEnumFromArray, generateTypeFromArray, generateAsConstFromArray, generateInterfaceFromArray.

Notes

• The library has zero runtime dependencies. Build with tsc.
• For enum mode, string values must be valid TypeScript identifiers to become keys; otherwise the file falls back to exporting a const array.
• For asconst and interface modes:
  • String values that are valid TypeScript identifiers use the value as the property key
  • Invalid identifiers use ITEM_${index} as the property key
  • Number values use VALUE_${number} as the property key

Contributing

1. Fork the repository.
2. Create a new branch: git checkout -b feature-name.
3. Commit your changes: git commit -m 'Add some feature'.
4. Push to the branch: git push origin feature-name.
5. Open a pull request.

License

Distributed under the MIT License. See the LICENSE file for more details.