dprint-node: Fast Code Formatter API for Node.js

Common errors

• Error: Cannot find module 'dprint-node'

  cause The 'dprint-node' package is not installed or not resolvable in the current environment.
  fix Run `npm install dprint-node` or `yarn add dprint-node` to add the package to your project dependencies.

• TypeError: dprint.format is not a function

  cause This typically occurs when trying to destructure the `dprint` object or using an incorrect import/require syntax that does not yield the expected default export object with the `format` method.
  fix Ensure you are using `const dprint = require('dprint-node');` for CommonJS or `import dprint from 'dprint-node';` for ES Modules, as the library exports its primary functionality as a default object.

• Property 'someInvalidOption' does not exist on type 'object' (or similar type error for config)

  cause You are passing a configuration option that is not recognized or correctly typed by the `dprint` formatter's schema for the given file type, or your TypeScript environment cannot correctly infer the type.
  fix Consult the official `dprint` plugin configuration documentation (e.g., `dprint.dev/plugins/typescript/config/`) for valid options. Ensure the option name and value type match the expected schema.

Warnings

• gotcha Versions prior to `1.0.5` had missing type declarations, which could lead to TypeScript compilation errors for users leveraging the library's types.
  Fix: Upgrade to `dprint-node@1.0.5` or later to ensure complete type declarations are available.
• breaking Versions prior to `1.0.3` could experience crashes on Apple Silicon (M1/M2) machines due to issues with the underlying `napi-rs` bindings.
  Fix: Update to `dprint-node@1.0.3` or newer to resolve the stability issues on Apple Silicon devices.
• gotcha The configuration options for `dprint.format`'s third parameter are defined externally by `dprint` plugins (e.g., TypeScript plugin config on dprint.dev). `dprint-node` itself might not provide granular, explicitly exported TypeScript types for all possible configuration properties, meaning misconfigured options might only manifest as runtime errors.
  Fix: Always refer to the official `dprint` plugin configuration documentation (e.g., `dprint.dev/plugins/typescript/config/`) to ensure correct and valid options are passed. Consider creating a local TypeScript interface for your configuration objects based on the dprint schema for better type safety.

Install

• npm install dprint-node npm
• yarn add dprint-node yarn
• pnpm add dprint-node pnpm

Imports

• dprint

  const dprint = require('dprint-node');

  CommonJS import for the main dprint object.
• dprint

  import dprint from 'dprint-node';

  ES Modules default import. This is common for packages shipping types and a single primary export.
• Formatting Configuration
  wrong:

  import { Configuration } from 'dprint-node';

  correct:

  import type { Configuration } from 'dprint-node/types';

  While dprint-node ships types, the explicit Configuration type might be located in a subpath or inferred by the `dprint.format` function's third argument. Refer to dprint.dev for detailed config options, as `dprint-node` acts as a wrapper. For robust typing, consider defining a local interface or consulting the package's `.d.ts` files.

Quickstart

This quickstart demonstrates how to format a TypeScript code string using `dprint-node` with custom configuration options for line width, semi-colons, indentation, and quote style, logging both the original and formatted output.

import dprint from 'dprint-node';

const filePath = './src/example.ts';
const unformattedCode = `
function  greet( name :  string ) { 
  console.log( `Hello, ${ name }!` )
}
`;

try {
  const formattedCode = dprint.format(filePath, unformattedCode, {
    lineWidth: 120,
    semiColons: "always",
    indentWidth: 2,
    quoteStyle: "alwaysSingle"
  });
  console.log('Original code:\n', unformattedCode);
  console.log('\nFormatted code:\n', formattedCode);
} catch (error) {
  console.error("Error formatting code:", error.message);
}