new way to pass the configuration to the encodings

README.md

@@ -43,102 +43,64 @@ as compressing will transform the body.
 
 #### Options
 
-`compression()` accepts these properties in the options object. In addition to
-those listed below, [zlib](http://nodejs.org/api/zlib.html) options may be
-passed in to the options object or
-[brotli](https://nodejs.org/api/zlib.html#zlib_class_brotlioptions) options.
+`compression()` accepts these properties in the options object.
 
-##### chunkSize
+##### encodings
 
-Type: `Number`<br>
-Default: `zlib.constants.Z_DEFAULT_CHUNK`, or `16384`.
+Type: `Object`<br>
 
-See [Node.js documentation](http://nodejs.org/api/zlib.html#zlib_memory_usage_tuning)
-regarding the usage.
+Handles the configurations for each encoding. Setting options.encodings[encoding] = false will disable that encoding.
 
-##### filter
-
-Type: `Function`
-
-A function to decide if the response should be considered for compression.
-This function is called as `filter(req, res)` and is expected to return
-`true` to consider the response for compression, or `false` to not compress
-the response.
-
-The default filter function uses the [compressible](https://www.npmjs.com/package/compressible)
-module to determine if `res.getHeader('Content-Type')` is compressible.
-
-##### level
-
-Type: `Number`<br>
-Default: `zlib.constants.Z_DEFAULT_COMPRESSION`, or `-1`
-
-The level of zlib compression to apply to responses. A higher level will result
-in better compression, but will take longer to complete. A lower level will
-result in less compression, but will be much faster.
-
-This is an integer in the range of `0` (no compression) to `9` (maximum
-compression). The special value `-1` can be used to mean the "default
-compression level", which is a default compromise between speed and
-compression (currently equivalent to level 6).
-
-  - `-1` Default compression level (also `zlib.constants.Z_DEFAULT_COMPRESSION`).
-  - `0` No compression (also `zlib.constants.Z_NO_COMPRESSION`).
-  - `1` Fastest compression (also `zlib.constants.Z_BEST_SPEED`).
-  - `2`
-  - `3`
-  - `4`
-  - `5`
-  - `6` (currently what `zlib.constants.Z_DEFAULT_COMPRESSION` points to).
-  - `7`
-  - `8`
-  - `9` Best compression (also `zlib.constants.Z_BEST_COMPRESSION`).
-
-**Note** in the list above, `zlib` is from `zlib = require('zlib')`.
+Example:
 
-##### memLevel
+```js
+const compression = require('compression')
+const express = require('express')
+
+const app = express()
+
+app.use(
+  compression({
+    encodings: {
+      br: {
+        params: {
+          [zlib.constants.BROTLI_PARAM_QUALITY]: 6
+        }
+      },
+      gzip: {
+        level: zlib.constants.Z_BEST_SPEED
+      },
+      deflate: false // Disable Deflate compression
+    }
+  })
+)
+```
 
-Type: `Number`<br>
-Default: `zlib.constants.Z_DEFAULT_MEMLEVEL`, or `8`
+###### Supported Encodings
 
-This specifies how much memory should be allocated for the internal compression
-state and is an integer in the range of `1` (minimum level) and `9` (maximum
-level).
+- **`br` (Brotli):**
 
-See [Node.js documentation](http://nodejs.org/api/zlib.html#zlib_memory_usage_tuning)
-regarding the usage.
+This specifies the options for configuring Brotli. See [Node.js documentation](https://nodejs.org/api/zlib.html#class-brotlioptions) for a complete list of available options.
 
-##### brotli
+- **gzip:**
 
-Type: `Object`
+This specifies the options for configuring gzip. See [Node.js documentation](https://nodejs.org/api/zlib.html#class-options) for a complete list of available options.
 
-This specifies the options for configuring Brotli. See [Node.js documentation](https://nodejs.org/api/zlib.html#class-brotlioptions) for a complete list of available options.
+- **deflate:**
 
+This specifies the options for configuring deflate. See [Node.js documentation](https://nodejs.org/api/zlib.html#class-options) for a complete list of available options.
 
-##### strategy
-
-Type: `Number`<br>
-Default: `zlib.constants.Z_DEFAULT_STRATEGY`
+##### filter
 
-This is used to tune the compression algorithm. This value only affects the
-compression ratio, not the correctness of the compressed output, even if it
-is not set appropriately.
+Type: `Function`
 
-  - `zlib.constants.Z_DEFAULT_STRATEGY` Use for normal data.
-  - `zlib.constants.Z_FILTERED` Use for data produced by a filter (or predictor).
-    Filtered data consists mostly of small values with a somewhat random
-    distribution. In this case, the compression algorithm is tuned to
-    compress them better. The effect is to force more Huffman coding and less
-    string matching; it is somewhat intermediate between `zlib.constants.Z_DEFAULT_STRATEGY`
-    and `zlib.constants.Z_HUFFMAN_ONLY`.
-  - `zlib.constants.Z_FIXED` Use to prevent the use of dynamic Huffman codes, allowing
-    for a simpler decoder for special applications.
-  - `zlib.constants.Z_HUFFMAN_ONLY` Use to force Huffman encoding only (no string match).
-  - `zlib.constants.Z_RLE` Use to limit match distances to one (run-length encoding).
-    This is designed to be almost as fast as `zlib.constants.Z_HUFFMAN_ONLY`, but give
-    better compression for PNG image data.
+A function to decide if the response should be considered for compression.
+This function is called as `filter(req, res)` and is expected to return
+`true` to consider the response for compression, or `false` to not compress
+the response.
 
-**Note** in the list above, `zlib` is from `zlib = require('zlib')`.
+The default filter function uses the [compressible](https://www.npmjs.com/package/compressible)
+module to determine if `res.getHeader('Content-Type')` is compressible.
 
 ##### threshold
 
@@ -154,14 +116,6 @@ at the time the response headers are written, then it is assumed the response is
 _over_ the threshold. To guarantee the response size can be determined, be sure
 set a `Content-Length` response header.
 
-##### windowBits
-
-Type: `Number`<br>
-Default: `zlib.constants.Z_DEFAULT_WINDOWBITS`, or `15`
-
-See [Node.js documentation](http://nodejs.org/api/zlib.html#zlib_memory_usage_tuning)
-regarding the usage.
-
 ##### enforceEncoding
 
 Type: `String`<br>

index.js

@@ -36,11 +36,9 @@ module.exports.filter = shouldCompress
  * @private
  */
 var cacheControlNoTransformRegExp = /(?:^|,)\s*?no-transform\s*?(?:,|$)/
-var SUPPORTED_ENCODING = ['br', 'gzip', 'deflate', 'identity']
+var ENCODING_OPTIONS = ['br', 'gzip', 'deflate']
 var PREFERRED_ENCODING = ['br', 'gzip']
 
-var encodingSupported = ['gzip', 'deflate', 'identity', 'br']
-
 /**
  * Compress response data with gzip / deflate.
  *
@@ -50,12 +48,14 @@ var encodingSupported = ['gzip', 'deflate', 'identity', 'br']
  */
 
 function compression (options) {
-  var opts = options || {}
-  var optsBrotli = {
-    ...opts.brotli,
+  const opts = options || {}
+  const encodingOpts = opts?.encodings
+  const encodingSupported = ENCODING_OPTIONS.filter(enc => encodingOpts?.[enc] !== false)
+  const optsBrotli = {
+    ...encodingOpts?.br,
     params: {
       [zlib.constants.BROTLI_PARAM_QUALITY]: 4, // set the default level to a reasonable value with balanced speed/ratio
-      ...opts.brotli?.params
+      ...encodingOpts?.br?.params
     }
   }
 
@@ -187,10 +187,10 @@ function compression (options) {
 
       // compression method
       var negotiator = new Negotiator(req)
-      var method = negotiator.encoding(SUPPORTED_ENCODING, PREFERRED_ENCODING)
+      var method = negotiator.encoding(encodingSupported, PREFERRED_ENCODING)
 
       // if no method is found, use the default encoding
-      if (!req.headers['accept-encoding'] && encodingSupported.indexOf(enforceEncoding) !== -1) {
+      if (!req.headers['accept-encoding'] && encodingSupported.includes(enforceEncoding)) {
         method = enforceEncoding
       }
 
@@ -202,11 +202,13 @@ function compression (options) {
 
       // compression stream
       debug('%s compression', method)
-      stream = method === 'gzip'
-        ? zlib.createGzip(opts)
-        : method === 'br'
-          ? zlib.createBrotliCompress(optsBrotli)
-          : zlib.createDeflate(opts)
+      if (method === 'gzip') {
+        stream = zlib.createGzip(encodingOpts?.gzip)
+      } else if (method === 'br') {
+        stream = zlib.createBrotliCompress(optsBrotli)
+      } else if (method === 'deflate') {
+        stream = zlib.createDeflate(encodingOpts?.deflate)
+      }
 
       // add buffered listeners to stream
       addListeners(stream, stream.on, listeners)