Configuration

EcmaCraft reads config from one of these files in your project root:

• ecmacraft.config.mjs
• ecmacraft.config.js
• ecmacraft.config.cjs
• ecmacraft.config.mts
• ecmacraft.config.ts
• ecmacraft.config.cts

The config is merged with EcmaCraft defaults, so you only need to define the fields you want to override.

Example

import { defineConfig } from 'ecmacraft/config';

export default defineConfig({
  development: {
    paperVersion: 'latest',
    javaArgs: ['-Xmx2G', '-Xms512M'],
    reloadType: 'soft',
    serverProperties: {
      'online-mode': false,
      'level-seed': 'ecmacraft-local-seed',
      'server-port': 25566,
      'query.port': 25566,
      motd: 'EcmaCraft Local Dev Server',
    },
    esbuildConfig: {},
  },
  production: {
    paperVersion: 'latest',
    esbuildConfig: {},
  },
});

Key Fields

development.paperVersion

PaperMC version hint for dev server setup (for example latest or 1.21).

development.javaArgs

JVM arguments used when launching the local Paper process.

development.reloadType

Controls what happens after a successful rebuild:

• soft: runs ecmacraft-reload
• hard: runs reload confirm
• none: no command is sent

development.esbuildConfig

Extra esbuild options merged into dev bundling.

development.serverProperties

An object used to generate .ecmacraft/development/server.properties before the server starts.

Use this for all common server tuning during local development:

• world seed and world generation,
• online/offline mode,
• server/query/rcon ports,
• simulation/view distance,
• whitelist, MOTD, and gameplay defaults.

Example: seed + offline mode + custom ports

export default defineConfig({
  development: {
    serverProperties: {
      'online-mode': false,
      'level-seed': 'my-seeded-test-world',
      'server-port': 25570,
      'query.port': 25570,
      'rcon.port': 25580,
      'enable-rcon': true,
      'rcon.password': 'local-dev-only',
    },
  },
});

Example: multiple local projects without port collision

export default defineConfig({
  development: {
    serverProperties: {
      'server-port': 25571,
      'query.port': 25571,
      'online-mode': false,
      motd: 'Plugin A dev server',
    },
  },
});

How values are written

• boolean values become true / false,
• numbers are serialized as numeric strings,
• strings are written as-is with Java properties escaping where required.

So a config value like:

{ 'level-type': 'minecraft:normal' }

is emitted correctly in server.properties format.

production.esbuildConfig

Extra esbuild options merged into production bundling.