diff --git a/archive/archive.js b/archive/archive.js
index cd88395..3a61807 100644
--- a/archive/archive.js
+++ b/archive/archive.js
@@ -2,6 +2,7 @@
  * archive.js
  *
  * Provides base functionality for unarchiving.
+ * DEPRECATED: Use decompress.js instead.
  *
  * Licensed under the MIT License
  *
@@ -12,7 +13,9 @@ import { UnarchiveAppendEvent, UnarchiveErrorEvent, UnarchiveEvent, UnarchiveEve
          UnarchiveExtractEvent, UnarchiveFinishEvent, UnarchiveInfoEvent,
          UnarchiveProgressEvent, UnarchiveStartEvent, Unarchiver,
          UnrarrerInternal, UntarrerInternal, UnzipperInternal,
-         getUnarchiverInternal } from './archive-internal.js';
+         getUnarchiverInternal } from './decompress-internal.js';
+
+console.warn(`Stop using archive.js and use decompress.js instead. This module will be removed.`);
 
 export {
   UnarchiveAppendEvent,
diff --git a/archive/compress.js b/archive/compress.js
index 1a72ee2..ab73397 100644
--- a/archive/compress.js
+++ b/archive/compress.js
@@ -1,6 +1,4 @@
 
-import { ByteBuffer } from '../io/bytebuffer.js';
-
 // NOTE: THIS IS A VERY HACKY WORK-IN-PROGRESS! THE API IS NOT FROZEN! USE AT YOUR OWN RISK!
 
 /**
@@ -10,9 +8,35 @@ import { ByteBuffer } from '../io/bytebuffer.js';
  * @property {ArrayBuffer} fileData The bytes of the file.
  */
 
+/**
+ * @readonly
+ * @enum {number}
+ */
+export const ZipCompressionMethod = {
+  STORE: 0, // Default.
+  // DEFLATE: 8,
+};
+
+// export const DeflateCompressionMethod = {
+//   NO_COMPRESSION: 0,
+//   COMPRESSION_FIXED_HUFFMAN: 1,
+//   COMPRESSION_DYNAMIC_HUFFMAN: 2,
+// }
+
+/**
+ * Data elements are packed into bytes in order of increasing bit number within the byte,
+   i.e., starting with the least-significant bit of the byte.
+ * Data elements other than Huffman codes are packed starting with the least-significant bit of the
+   data element.
+ * Huffman codes are packed starting with the most-significant bit of the code.
+ */
+
 /**
  * @typedef CompressorOptions
  * @property {string} pathToBitJS A string indicating where the BitJS files are located.
+ * @property {ZipCompressionMethod} zipCompressionMethod
+ * @property {DeflateCompressionMethod=} deflateCompressionMethod Only present if
+ *     zipCompressionMethod is set to DEFLATE.
  */
 
 /**
@@ -30,6 +54,7 @@ export const CompressStatus = {
 /**
  * A thing that zips files.
  * NOTE: THIS IS A VERY HACKY WORK-IN-PROGRESS! THE API IS NOT FROZEN! USE AT YOUR OWN RISK!
+ * TODO: Make a streaming / event-driven API.
  */
 export class Zipper {
   /**
@@ -43,6 +68,12 @@ export class Zipper {
      */
     this.pathToBitJS = options.pathToBitJS || '/';
 
+    /**
+     * @type {ZipCompressionMethod}
+     * @private
+     */
+    this.zipCompressionMethod = options.zipCompressionMethod || ZipCompressionMethod.STORE;
+
     /**
      * Private web worker initialized during start().
      * @type {Worker}
@@ -80,9 +111,13 @@ export class Zipper {
   }
 
   /**
+   * Send in a set of files to be compressed. Set isLastFile to true if no more files are to added
+   * at some future state. The Promise will not resolve until isLastFile is set to true either in
+   * this method or in appendFiles().
    * @param {FileInfo[]} files
    * @param {boolean} isLastFile
-   * @returns {Promise<Uint8Array>} A Promise that contains the entire zipped archive.
+   * @returns {Promise<Uint8Array>} A Promise that will contain the entire zipped archive as an array
+   *     of bytes.
    */
   start(files, isLastFile) {
     return new Promise((resolve, reject) => {
diff --git a/archive/archive-internal.js b/archive/decompress-internal.js
similarity index 99%
rename from archive/archive-internal.js
rename to archive/decompress-internal.js
index 063a9c3..37ab2ad 100644
--- a/archive/archive-internal.js
+++ b/archive/decompress-internal.js
@@ -207,11 +207,15 @@ export class UnarchiveExtractEvent extends UnarchiveEvent {
      */
     this.pathToBitJS_ = options.pathToBitJS || '/';
 
-    /** @orivate {boolean} */
+    /**
+     * @orivate
+     * @type {boolean}
+     */
     this.debugMode_ = !!(options.debug);
 
     /**
      * A map from event type to an array of listeners.
+     * @private
      * @type {Map.<string, Array>}
      */
     this.listeners_ = {};
@@ -221,8 +225,8 @@ export class UnarchiveExtractEvent extends UnarchiveEvent {
 
     /**
      * Private web worker initialized during start().
-     * @type {Worker}
      * @private
+     * @type {Worker}
      */
     this.worker_ = null;
   }
diff --git a/archive/decompress.js b/archive/decompress.js
new file mode 100644
index 0000000..e5cc5e6
--- /dev/null
+++ b/archive/decompress.js
@@ -0,0 +1,84 @@
+/**
+ * decompress.js
+ *
+ * Provides base functionality for unarchiving/decompression.
+ *
+ * Licensed under the MIT License
+ *
+ * Copyright(c) 2021 Google Inc.
+ */
+
+ import { UnarchiveAppendEvent, UnarchiveErrorEvent, UnarchiveEvent, UnarchiveEventType,
+  UnarchiveExtractEvent, UnarchiveFinishEvent, UnarchiveInfoEvent,
+  UnarchiveProgressEvent, UnarchiveStartEvent, Unarchiver,
+  UnrarrerInternal, UntarrerInternal, UnzipperInternal,
+  getUnarchiverInternal } from './decompress-internal.js';
+
+export {
+  UnarchiveAppendEvent,
+  UnarchiveErrorEvent,
+  UnarchiveEvent,
+  UnarchiveEventType,
+  UnarchiveExtractEvent,
+  UnarchiveFinishEvent,
+  UnarchiveInfoEvent,
+  UnarchiveProgressEvent,
+  UnarchiveStartEvent,
+  Unarchiver,
+} 
+
+/**
+* All extracted files returned by an Unarchiver will implement
+* the following interface:
+*/
+
+/**
+* @typedef UnarchivedFile
+* @property {string} filename
+* @property {Uint8Array} fileData
+*/
+
+/**
+* The goal is to make this testable - send getUnarchiver() an array buffer of
+* an archive, call start on the unarchiver, expect the returned result.
+*
+* Problem: It relies on Web Workers, and that won't work in a nodejs context.
+* Solution: Make archive.js very thin, have it feed web-specific things into
+*           an internal module that is isomorphic JavaScript.
+*
+* TODO:
+* - write unit tests for archive-internal.js that use the nodejs Worker
+*   equivalent.
+* - maybe use @pgriess/node-webworker or @audreyt/node-webworker-threads or
+*   just node's worker_threads ?
+*/
+
+const createWorkerFn = (scriptFilename) => new Worker(scriptFilename);
+
+// Thin wrappers of compressors for clients who want to construct a specific
+// unarchiver themselves rather than use getUnarchiver().
+export class Unzipper extends UnzipperInternal {
+  constructor(ab, options) { super(ab, createWorkerFn, options); }
+}
+
+export class Unrarrer extends UnrarrerInternal {
+  constructor(ab, options) { super(ab, createWorkerFn, options); }
+}
+
+export class Untarrer extends UntarrerInternal {
+  constructor(ab, options) { super(ab, createWorkerFn, options); }
+}
+
+/**
+* Factory method that creates an unarchiver based on the byte signature found
+* in the arrayBuffer.
+* @param {ArrayBuffer} ab The ArrayBuffer to unarchive. Note that this ArrayBuffer
+*     must not be referenced after calling this method, as the ArrayBuffer is marked
+*     as Transferable and sent to a Worker thread once start() is called.
+* @param {Object|string} options An optional object of options, or a string
+*     representing where the path to the unarchiver script files.
+* @return {Unarchiver}
+*/
+export function getUnarchiver(ab, options = {}) {
+  return getUnarchiverInternal(ab, createWorkerFn, options);
+}
diff --git a/archive/unzip.js b/archive/unzip.js
index f0b3a12..473de5b 100644
--- a/archive/unzip.js
+++ b/archive/unzip.js
@@ -493,7 +493,7 @@ function inflate(compressedData, numDecompressedBytes) {
   // Bit stream representing the compressed data.
   /** @type {bitjs.io.BitStream} */
   const bstream = new bitjs.io.BitStream(compressedData.buffer,
-    false /* rtl */,
+    false /* mtl */,
     compressedData.byteOffset,
     compressedData.byteLength);
   /** @type {bitjs.io.ByteBuffer} */
diff --git a/tests/archive-testfiles/README.md b/tests/archive-testfiles/README.md
index f965951..38d1396 100644
--- a/tests/archive-testfiles/README.md
+++ b/tests/archive-testfiles/README.md
@@ -2,4 +2,4 @@
 
   1. Create a zip or rar file with just one file inside it.
   2. Use test-uploader.html and choose the archived file and the unarchived file.
-  3. Paste that jSON output into a test json file.
+  3. Paste that JSON output into a test json file.
diff --git a/tests/zipper-test.js b/tests/zipper-test.js
index 2117602..e0437ff 100644
--- a/tests/zipper-test.js
+++ b/tests/zipper-test.js
@@ -1,5 +1,5 @@
 
-import { Zipper } from '../archive/compress.js';
+import { Zipper, ZipCompressionMethod } from '../archive/compress.js';
 
 const result = document.querySelector('#result');
 const fileInputEl = document.querySelector('#zip-tester');
@@ -36,7 +36,10 @@ async function getFiles(fileChangeEvt) {
 
   result.innerHTML = `Loaded files`;
 
-  const zipper = new Zipper({ pathToBitJS: '../' });
+  const zipper = new Zipper({
+    pathToBitJS: '../',
+    zipCompressionMethod: ZipCompressionMethod.DEFLATE,
+  });
   byteArray = await zipper.start(fileInfos, true);
   result.innerHTML = `Zipping done`;
   saveButtonEl.style.display = '';