Installation

Two npm packages, one engine. This chapter covers @goplasmatic/datalogic-wasm, the WASM build: pick it for browsers, edge runtimes, Deno, and anywhere portability matters. For Node.js servers, prefer the native @goplasmatic/datalogic-node package (napi), which calls the Rust core without a WebAssembly layer.

The @goplasmatic/datalogic-wasm package provides WebAssembly bindings for the datalogic-rs engine, so you can evaluate JSONLogic from JavaScript and TypeScript.

Package Installation

# npm
npm install @goplasmatic/datalogic-wasm

# yarn
yarn add @goplasmatic/datalogic-wasm

# pnpm
pnpm add @goplasmatic/datalogic-wasm

The package declares Node 18 or newer (engines.node) for the Node.js target.

Build Targets

The package includes three build targets, one per environment:

Automatic Target Selection

The package’s exports field selects a target by export condition:

// Browser/Bundler - the `import` condition resolves to the web target
import init, { Engine } from '@goplasmatic/datalogic-wasm';

// Node.js - the `node` condition resolves to the nodejs target
const { Engine } = require('@goplasmatic/datalogic-wasm');

Explicit Target Import

If you need a specific target:

// Web target (ES modules with init)
import init, { Engine } from '@goplasmatic/datalogic-wasm/web';

// Bundler target (no init; the module instantiates on import)
import { Engine } from '@goplasmatic/datalogic-wasm/bundler';

// Node.js target
import { Engine } from '@goplasmatic/datalogic-wasm/nodejs';

The bundler target imports datalogic_wasm_bg.wasm as an ES module, so it needs Webpack’s experiments.asyncWebAssembly (or the equivalent in your bundler); see Bundler Configuration.

WASM Initialization

For browser and bundler environments, initialize the WASM module before you use any export:

import init, { Engine } from '@goplasmatic/datalogic-wasm';

// Initialize once at application startup
await init();

// Then build an engine and evaluate
const engine = new Engine();
const result = engine.evalStr('{"==": [1, 1]}', '{}'); // "true"

On Node.js, use the exports right after import, with no initialization. Do not call init() there: with the bare specifier, Node resolves to the CommonJS nodejs target, so a default import binds init to the module namespace object and await init() throws TypeError: init is not a function. Code that has to run in both places should guard the call:

import init, { Engine } from '@goplasmatic/datalogic-wasm';
if (typeof init === 'function') await init(); // browser: loads the module; Node: no-op

Or import from @goplasmatic/datalogic-wasm/nodejs and skip init.

TypeScript Support

The package includes TypeScript declarations. No additional @types package is needed.

import init, { Engine, Rule } from '@goplasmatic/datalogic-wasm';

await init();
const engine = new Engine();
const rule: Rule = engine.compile('{"==": [1, 1]}');
const result: string = rule.evaluate('{}'); // "true"

The declarations mark the deprecated exports (evaluate, evaluateWithTrace, CompiledRule, Session.evaluateNumber) with @deprecated, so your editor flags them; see Deprecated APIs.

Bundle Size

The WASM binary is a single self-contained module: 5,197,441 bytes (about 5.2 MB) uncompressed and 1,002,235 bytes (about 1.0 MB) gzipped in the 5.8.0 release build. It compiles in the IANA timezone database that the datetime feature’s format_date / parse_date timezone arguments use. Size-sensitive embedders building from source can shrink it by setting CHRONO_TZ_TIMEZONE_FILTER to the zones they need; see Building from source.

CDN Usage

For prototypes or simple pages, you can load the module from a CDN:

<script type="module">
  import init, { Engine } from 'https://unpkg.com/@goplasmatic/datalogic-wasm@latest/web/datalogic_wasm.js';

  async function run() {
    await init();
    const engine = new Engine();
    console.log(engine.evalStr('{"==": [1, 1]}', '{}')); // "true"
  }

  run();
</script>

Next Steps

• Quick Start - Basic usage examples
• API Reference - Functions, classes, configuration, and error shapes
• Framework Integration - React, Vue, and bundler setup