CtrlK
BlogDocsLog inGet started
Tessl Logo

tessl/npm-rollup-plugin-terser

Rollup plugin to minify generated ES bundles using Terser with worker-based parallel processing

—

Pending
Quality

Pending

Does it follow best practices?

Impact

Pending

No eval scenarios have been run

SecuritybySnyk

Pending

The risk profile of this skill

Overview
Eval results
Files

Rollup Plugin Terser

Rollup Plugin Terser is a plugin for Rollup that integrates Terser for minifying JavaScript bundles during the build process. It provides worker-based parallel processing for efficient minification, automatic configuration based on output format, and comprehensive options for controlling the minification process.

Package Information

  • Package Name: rollup-plugin-terser
  • Package Type: npm
  • Language: JavaScript/TypeScript
  • Installation: npm install rollup-plugin-terser --save-dev

Core Imports

import { terser } from "rollup-plugin-terser";

For CommonJS:

const { terser } = require("rollup-plugin-terser");

Basic Usage

import { rollup } from "rollup";
import { terser } from "rollup-plugin-terser";

// Basic usage with default options
export default {
  input: "src/index.js",
  output: {
    file: "dist/bundle.min.js",
    format: "iife"
  },
  plugins: [terser()]
};

// With custom options
export default {
  input: "src/index.js",
  output: {
    file: "dist/bundle.min.js",
    format: "esm"
  },
  plugins: [
    terser({
      compress: {
        drop_console: true
      },
      format: {
        comments: false
      },
      numWorkers: 4
    })
  ]
};

Architecture

Rollup Plugin Terser is built around several key components:

  • Plugin Factory: The terser() function that creates and configures the Rollup plugin instance
  • Worker Management: Uses jest-worker for multi-threaded minification to improve performance
  • Format Detection: Automatically configures Terser options based on Rollup's output format (ESM, CommonJS, etc.)
  • Options Processing: Merges user options with format-specific defaults and handles plugin-specific options
  • Error Handling: Enhanced error reporting with code frame context using Babel's code-frame

Capabilities

Terser Plugin Factory

Creates a Rollup plugin instance configured for JavaScript minification using Terser.

/**
 * Creates a Rollup plugin for minifying JavaScript code using Terser
 * @param options - Configuration options extending Terser's MinifyOptions
 * @returns Rollup Plugin object with renderChunk method
 */
function terser(options?: Options): Plugin;

interface Options extends Omit<MinifyOptions, "sourceMap"> {
  /**
   * Amount of workers to spawn for parallel processing
   * Defaults to the number of CPUs minus 1
   */
  numWorkers?: number;
}

interface Plugin {
  /** Plugin identifier */
  name: "terser";
  /** Async method called by Rollup to process each chunk */
  renderChunk(code: string, chunk: ChunkInfo, outputOptions: OutputOptions): Promise<TransformResult>;
}

Configuration Features:

  • Automatic Format Detection: The plugin automatically sets optimal Terser options based on Rollup's output format:

    • module: true when format is esm or es
    • toplevel: true when format is cjs
    • sourceMap inferred from Rollup's sourcemap settings

  • Worker-based Processing: Uses jest-worker to spawn multiple processes for parallel minification, improving performance on multi-core systems

  • Name Cache Support: Supports Terser's name caching feature for consistent variable names across builds

Usage Examples:

// Basic minification
terser()

// Custom compression settings
terser({
  compress: {
    drop_console: true,
    drop_debugger: true,
    pure_funcs: ["console.log", "console.warn"]
  }
})

// Preserve specific comments (e.g., licenses)
terser({
  format: {
    comments: function(node, comment) {
      const text = comment.value;
      const type = comment.type;
      if (type === "comment2") {
        // multiline comment
        return /@preserve|@license|@cc_on/i.test(text);
      }
    }
  }
})

// Keep all comments
terser({
  format: {
    comments: "all"
  }
})

// Custom worker configuration
terser({
  numWorkers: 2,
  compress: {
    passes: 2
  }
})

// Name cache for consistent builds
const nameCache = {};
terser({
  nameCache: nameCache,
  mangle: {
    properties: true
  }
})

Types

interface Options extends Omit<MinifyOptions, "sourceMap"> {
  /**
   * Amount of workers to spawn for parallel processing
   * Defaults to the number of CPUs minus 1
   */
  numWorkers?: number;
}

interface Plugin {
  /** Plugin identifier */
  name: "terser";
  /** Async method called by Rollup to process each chunk */
  renderChunk(
    code: string,
    chunk: ChunkInfo,
    outputOptions: OutputOptions
  ): Promise<TransformResult>;
}

interface ChunkInfo {
  fileName: string;
  name: string;
  isEntry: boolean;
  isDynamicEntry: boolean;
  facadeModuleId: string | null;
  moduleIds: string[];
  exports: string[];
  [key: string]: any;
}

interface OutputOptions {
  format: "es" | "esm" | "cjs" | "iife" | "umd" | "system" | "amd";
  sourcemap?: boolean | "inline" | "hidden";
  [key: string]: any;
}

interface TransformResult {
  code: string;
  map?: any; // Source map object
}

Error Handling

The plugin provides enhanced error reporting with code context:

  • Parse Errors: When Terser encounters syntax errors, the plugin displays the problematic code with line numbers and context using Babel's code-frame
  • Worker Errors: Errors from worker processes are properly propagated and formatted
  • Configuration Errors: Invalid configuration options (like deprecated sourceMap or sourcemap options) throw descriptive errors

Deprecated Options:

The plugin will throw errors for these deprecated options:

  • sourceMap - Now inferred from Rollup options
  • sourcemap - Now inferred from Rollup options

Performance Notes

  • Worker Management: Workers are created per plugin instance and reused across chunks in the same build
  • Memory Efficiency: Workers are terminated when all chunks are processed to free memory
  • CPU Utilization: Default worker count is CPU cores minus 1 for optimal performance without blocking the system
Workspace
tessl
Visibility
Public
Created
Last updated
Describes
npmpkg:npm/rollup-plugin-terser@7.0.x
Publish Source
CLI
Badge
tessl/npm-rollup-plugin-terser badge