JavaScript guide

Get started with Duper in Node.JS and the browser with the @duper-js/node and @duper-js/wasm packages.

Installation

Node.js

npm install --save @duper-js/node

Vite

npm install --save @duper-js/wasm
npm install --save-dev vite-plugin-top-level-await vite-plugin-wasm

Add the following to vite.config.js:

import { defineConfig } from "vite";
import wasm from "vite-plugin-wasm";
import topLevelAwait from "vite-plugin-top-level-await";

export default defineConfig({
  plugins: [
    wasm(),
    topLevelAwait(),
    // Your other plugins...
  ],
});

Usage

import { parse, stringify } from "@duper-js/wasm";

const data = {
  name: "Wireless Headphones",
  price: 129.99,
  in_stock: true,
  tags: ["electronics", "audio"],
};

// Convert to Duper format
const duper_string = stringify(data);
console.log(duper_string);

// Convert back from Duper
const restored_data = parse(duper_string);
console.log(restored_data);

You can also manipulate parsed Duper values directly:

import { parse, stringify, DuperValue } from "@duper-js/wasm";

// Parse some input
const input = `
  Product({
    product_id: Uuid("1dd7b7aa-515e-405f-85a9-8ac812242609"),
    name: "Wireless Bluetooth Headphones",
    brand: "AudioTech",
    price: Decimal("129.99"),
    dimensions: (18.5, 15.2, 7.8),  // In centimeters
    weight: Kilograms(0.285),
    in_stock: true,
    specifications: {
      battery_life: Duration("30h"),
      noise_cancellation: true,
      connectivity: ["Bluetooth 5.0", "3.5mm Jack"],
    },
    image_thumbnail: Png(b64"iVBORw0KGgoAAAANSUhEUgAAAGQ="),
    tags: ["electronics", "audio", "wireless"],
    release_date: PlainDate('2023-11-15'),
    /* Warranty is optional */
    warranty_period: null,
    customer_ratings: {
      latest_review: r#"Absolutely ""astounding""!! 😎"#,
      average: 4.5,
      count: 127,
    },
    created_at: Instant('2023-11-17T21:50:43+00:00'),
  })
`;
const duper = parse(input);
console.log(duper.identifier); // Product
console.log(duper.value.in_stock.type); // boolean

// Convert to JSON
console.log(JSON.stringify(duper));

// Patch the Duper value and pretty-print it
const newTags = DuperValue.Tuple([
  DuperValue.String("music"),
  DuperValue.String("hi-fi", "DeprecatedTag"),
]);
duper.value.tags = newTags;
duper.value.image_thumbnail.identifier = null;
duper.value.weight.identifier = "Pounds";
delete duper.value.dimensions;
duper.value.test = DuperValue.Object({ foo: DuperValue.String("bar") });
console.log(stringify(duper, { indent: "  " }));