@jlarky/json-to-javascript

json-to-javascript

Convert JSON data to JavaScript code literals with smart handling of multiline strings.

This tool transforms JSON into properly formatted JavaScript code, automatically converting multiline strings into template literals with dedent support for clean indentation.

CLI Usage

Example: Converting JSON with Multiline Strings

Input file (input.json):

{
  "greeting": "Hello\nWorld",
  "message": "Line 1\nLine 2\nLine 3",
  "count": 42
}

Node.js:

npx @jlarky/json-to-javascript \
  --inputFile input.json \
  --outputFile output.ts \
  --useDedent true \
  --prefix "import dedent from 'dedent'; export const data = (" \
  --suffix ") as const" \
  --prettierOptions '{"parser":"babel-ts"}'

Bun:

bunx @jlarky/json-to-javascript \
  --inputFile input.json \
  --outputFile output.ts \
  --useDedent true \
  --prefix "import dedent from 'dedent'; export const data = (" \
  --suffix ") as const" \
  --prettierOptions '{"parser":"babel-ts"}'

Deno:

deno run --allow-sys=cpus --allow-env --allow-read=. --allow-write=. \
  jsr:@jlarky/json-to-javascript/cli \
  --inputFile input.json \
  --outputFile output.ts \
  --useDedent true \
  --prefix "import dedent from 'dedent'; export const data = (" \
  --suffix ") as const" \
  --prettierOptions '{"parser":"babel-ts"}'

Output file (output.ts):

import dedent from "dedent";
export const data = {
  greeting: dedent`
    Hello
    World
  `,
  message: dedent`
    Line 1
    Line 2
    Line 3
  `,
  count: 42,
} as const;

Basic Usage

npx @jlarky/json-to-javascript \
  --inputFile input.json \
  --outputFile output.js

This outputs the same JSON with default prefix ( and suffix ):

({
  greeting: "Hello\nWorld",
  message: "Line 1\nLine 2\nLine 3",
  count: 42,
});

The difference from the previous example: no custom prefix/suffix, import statement, or dedent - just the data wrapped in parentheses with escaped newlines.

CLI Options

json-to-javascript [options]

Required:
  --inputFile <path>              Input JSON file
  --outputFile <path>             Output JavaScript file

Optional:
  --prefix <string>               Prefix for output (default: "(")
  --suffix <string>               Suffix for output (default: ")")
  --usePrettier <boolean>         Format with Prettier (default: true)
  --prettierOptions <json>        Prettier options as JSON string
  --useDedent <boolean>           Convert multiline strings to template literals
  --dedentPrefix <string>         Prefix for dedent (default: " dedent")
  --dedentSuffix <string>         Suffix for dedent (default: "")
  --jsonStringifySpace <number>   Indentation spaces for JSON.stringify
  --help                          Show help

Installation

If you want to use the library in your code or install it locally:

If using Deno:

deno add jsr:@jlarky/json-to-javascript

If using Bun:

bunx jsr add @jlarky/json-to-javascript # or bun add @jlarky/json-to-javascript

If using Node.js:

npx jsr add @jlarky/json-to-javascript # or npm install @jlarky/json-to-javascript

Library Usage

import { jsonToJavascript } from "@jlarky/json-to-javascript";

const data = { name: "John", age: 30 };
const result = await jsonToJavascript(data);
console.log(result.code); // ({ name: "John", age: 30 });

Use Cases

• Generate configuration files from JSON
• Create test fixtures from JSON data
• Convert API responses to TypeScript constants
• Generate code with proper template literal formatting for multiline content

Development

See CONTRIBUTING.md for development setup, testing, and publishing guidelines.

License

MIT