slice2js

3.7.110 verified Fri May 01 auth: no javascript

slice2js is the official Slice-to-JavaScript compiler from ZeroC, part of the Ice RPC framework. It compiles Slice IDL files into JavaScript proxy and skeleton code for building networked applications. The current stable version is 3.7.110 (Ice 3.7.x series). Release cadence follows Ice releases, approximately every 6-12 months. Key differentiator: it's the native compiler for Ice's JavaScript mapping, tightly coupled with the @zeroc/ice npm package. Alternatives like protobuf or Thrift require separate toolchains.

Common errors

error Error: Cannot find module 'slice2js' ↓

cause slice2js is not installed or not in node_modules.

fix

Run 'npm install slice2js --save-dev' in your project directory.

error TypeError: slice2js.compile is not a function ↓

cause Incorrect import: using default import with ESM syntax.

fix

Use const slice2js = require('slice2js'); instead of import.

error slice2js: error: unknown option '--ice' ↓

cause The --ice option was removed in slice2js 3.7.0.

fix

Remove --ice from the arguments; Ice includes are added automatically.

error slice2js: error: Can't open file './Hello.ice' ↓

cause File path is relative to the current working directory, not the Slice file location.

fix

Use an absolute path or set the cwd option: slice2js.compile(['Hello.ice'], { cwd: __dirname }).

Warnings

breaking slice2js v3.8 drops support for Node.js <14 and changes the compiler API. ↓

fix Upgrade to Node.js >=14 and adjust code for any API changes.

breaking slice2js v3.7.0 removed the '--ice' option; Ice includes are now automatic. ↓

fix Remove '--ice' from args. The sliceDir property provides the path if needed.

deprecated The compile function returns a ChildProcess; consider using promises with child_process.execFile. ↓

fix Wrap compile in a promise or use child_process.execFile for simpler error handling.

gotcha slice2js must be installed in the same project as @zeroc/ice to ensure compatible versions. ↓

fix Install both as dependencies: npm install slice2js --save-dev && npm install @zeroc/ice

gotcha Relative paths in args are resolved from the current working directory, not from the Slice file location. ↓

fix Use absolute paths or set the 'cwd' option in the second argument to compile().

Install

npm install slice2js

yarn add slice2js

pnpm add slice2js

Imports

compile

wrong

import { compile } from 'slice2js';

correct

const slice2js = require('slice2js'); slice2js.compile(['File.ice']);

slice2js is a CommonJS module; no ESM export. Use require() only.

sliceDir

wrong

const { sliceDir } = require('slice2js');

correct

const slice2js = require('slice2js'); const dir = slice2js.sliceDir;

sliceDir is a property of the default export, not a named export.

default (require)
wrong
```
import slice2js from 'slice2js';
```
correct
```
const slice2js = require('slice2js');
```
slice2js is CommonJS-only; ES6 import does not work.

Quickstart

Demonstrates how to import slice2js, compile a Slice file, handle exit codes, and access the built-in Slice include path.

const slice2js = require('slice2js');
const path = require('path');

// Compile a Slice file
const child = slice2js.compile(['Hello.ice'], {
  cwd: '/path/to/slice',
  stdio: 'inherit'
});

child.on('close', (code) => {
  if (code !== 0) {
    console.error(`slice2js exited with code ${code}`);
    process.exit(code);
  } else {
    console.log('Compilation succeeded');
  }
});

console.log('Ice Slice directory:', slice2js.sliceDir);