Choose a version:
28% The original file has 104020 bytes (101.6k) and is available from the project website.
There you can find the official minified version, too, which brings down the size to 29171 bytes (28.5k, 28%).

After GZIP compression these minified files vary in size:
gzip -6 (default)
  10298 bytes (10.1k)
local copy
gzip -9
  10288 bytes (10.0k)
local copy
libdeflate -12
  10027 bytes (9.8k)
local copy
7zip -mx=9 -tgzip
  10016 bytes (9.8k)
local copy
kzip -s0 -rn -b1
  10016 bytes (9.8k)
local copy
pigz -11 -n
  10007 bytes (9.8k)
local copy
Zopfli
  9992 bytes (9.8k)
local copy

perma-link to the smallest file on my server:
http://minime.stephan-brumme.com/files/knockout/knockout-1.2.0.min.js

You will automatically get the smallest Knockout 1.2.0 file, ETag caching is available and
if your browser doesn't support GZIP decompression then the uncompressed version will be sent.

Currently best Zopfli settings

You can use my super-compressed files for whatever purpose you like as long as you respect the library's original license agreement.
There are no restrictions from my side - but please avoid hot-linking if you run a high-traffic website.

These command-line settings yielded the best compression ratio so far (Linux version of zopfli-krzymod):
zopfli --i100000 --mb8 --mls128 --bsr9 --lazy --ohh

(found December 18, 2015)
Description Value Parameter
iterations 100000  --i100000
maximum blocks 8  --mb8
maximum length score 128  --mls128
block splitting recursion 9  --bsr9
lazy matching in LZ77 yes  --lazy
optimized Huffman headers yes  --ohh
initial random W for iterations 1  --rw1
initial random Z for iterations 2  --rz2

Verify file integrity

After decompression, my uncompressed files are identical to the original ones:

MD5:
curl --silent --compressed http://knockoutjs.com/downloads/knockout-1.2.0.js --location | md5sum
04d65f0187009ec1b08ef9808ac297fb  -
curl --silent --compressed http://minime.stephan-brumme.com/files/knockout/knockout-1.2.0.min.zopfli.js.gz | md5sum
04d65f0187009ec1b08ef9808ac297fb  -

SHA1:
curl --silent --compressed http://knockoutjs.com/downloads/knockout-1.2.0.js --location | sha1sum
8a253b7bfc616b9c11e4b7018b91007250334151  -
curl --silent --compressed http://minime.stephan-brumme.com/files/knockout/knockout-1.2.0.min.zopfli.js.gz | sha1sum
8a253b7bfc616b9c11e4b7018b91007250334151  -

Other Versions

Available Knockout versions at minime.stephan-brumme.com:

3.4.2, 3.4.1, 3.4.0,
3.3.0,
3.2.0,
3.1.0,
3.0.0,
2.3.0,
2.2.1, 2.2.0,
2.1.0,
2.0.0,
1.2.1, 1.2.0,
1.1.2, 1.1.1, 1.1.0

The project site contains an overview how well these versions were compressed.
Other interesting projects are AngularJS, BackboneJS, Bootstrap, D3, Dojo, Ember, jQuery, lodash, React, Socket.IO, ThreeJS, UnderscoreJS and Vue.

Changelog

Best Zopfli parameters so far:
Size Improvement Parameters Found
9992 bytes -1 byte zopfli --i100000 --mls128 --bsr9 --lazy --ohh December 18, 2015 @ 23:19
9993 bytes -2 bytes zopfli --i1000 --mls2048 --bsr6 --lazy --ohh September 10, 2015 @ 11:59
9995 bytes zopfli --i100 --mls4096 --bsr13 --lazy --ohh September 10, 2015 @ 11:34

If there are multiple parameter sets yielding the same compressed size, only the first one found is shown.

Most recent activity on June 16, 2016 @ 14:37.

Heatmaps

This Zopfli heatmap visualizes how compression changes when modifying the --bsr and --mls parameter.
Cell's contents is the best filesize achieved (in bytes, hover with mouse over cells to see number of iterations).

Good parameters are green, bad are red. The best and worst are bold as well.
The brightness of the blue background color indicates how many iterations were processed:
10,000 or 100,000.
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
bsr \ mls
2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 32768
10001 10000 9999 10000 10000 10001 10001 9999 10000 9999 9999 10001 10000 10000 10001
10002 10009 10000 10001 10002 10002 10001 10000 10000 9994 9992 9998 9995 10001 10000
9998 10002 9998 10003 10000 10002 10001 10001 9999 10001 9992 9994 9994 9998 10000
10001 10002 9995 10001 9992 10003 9993 9995 10000 9993 9992 9994 9999 10001 10000
10001 10000 10000 10001 10002 10002 10001 10002 10003 9993 9993 9998 9994 10001 9993
9992 9992 9992 10001 10002 10002 9992 9996 9996 9995 9992 9998 9994 9994 9994
10002 10002 10000 10001 10002 10002 10002 10002 10002 9998 10000 9998 9994 10001 10000
9993 9992 9993 10001 10002 10002 9994 10001 10003 9993 9993 9994 9995 9995 9993
9992 9992 9993 10001 10002 10000 10002 9992 9999 9993 9993 9995 9994 9995 10000
9998 10002 9998 10001 10002 10002 10001 10001 9999 10000 9992 9992 9995 9998 10000
9992 9992 10006 10001 10002 10003 10001 10001 9999 9999 9992 9998 9994 9999 10000
9994 9994 9993 10001 9992 10002 10001 10002 10000 9994 9993 9994 9994 10001 10000
10002 10002 10001 10001 10002 10000 10000 9993 9995 9994 9992 9994 9999 10001 9999
10000 10000 9993 10001 10002 10000 10001 10002 10003 9994 9993 9998 9999 9998 9994
9992 9992 9992 9992 10002 10002 9993 9995 10000 9993 9993 9998 9995 9994 9994
10002 10002 10004 10001 10002 10003 10001 10002 10002 9995 9992 9998 9994 9998 10000
9993 9992 9993 10001 10002 10000 10001 9995 10002 9993 9993 9994 9999 9994 9994
10000 9992 9992 10001 10002 10003 10001 10001 10003 9993 9992 10000 9994 9998 9999
9994 9994 9992 10001 10002 10000 9998 10001 9994 9993 9994 9994 9994 9998 10000
9993 10000 9993 10001 10002 10003 10001 10001 9996 9993 9992 9994 9994 10001 9993
9994 9994 9994 10001 10002 10002 10001 9995 10000 9993 9992 9995 9994 9995 10000
10002 9992 9992 10001 10002 10002 10001 10001 10002 9994 9993 10000 9995 9995 9993
9993 10002 9992 10001 10003 10002 10001 10002 10000 9994 9994 9995 9995 10000 10000

Due to the Monte Carlo design of my search algorithm, not all parameters have reached the same number of iterations yet:
Iterations Min. Bytes Reduction Coverage
100 9994 bytes 100%
1,000 9993 bytes -1 byte 100%
10,000 9993 bytes 100%
100,000 9992 bytes -1 byte 20.29%
1,000,000
10,000,000

KZIP has far less options available for tuning/optimization. I only played around with the number of blocks (parameter -n):
Blocks Min. Bytes Compared To Best Zopfli Compared To Best KZIP
10016 bytes +24 bytes (+0.24%)
10016 bytes +24 bytes (+0.24%)
10046 bytes +54 bytes (+0.54%) +30 bytes
10075 bytes +83 bytes (+0.83%) +59 bytes
10074 bytes +82 bytes (+0.82%) +58 bytes
10101 bytes +109 bytes (+1.09%) +85 bytes
10142 bytes +150 bytes (+1.50%) +126 bytes
10177 bytes +185 bytes (+1.85%) +161 bytes
10212 bytes +220 bytes (+2.20%) +196 bytes

Non-DEFLATE Algorithms

Archivers based on completely different compression algorithms often produce superior results.
Unfortunately, browsers only support gzip compression at the moment.
Algorithm Program Parameters Size Compared To Best Zopfli
RAR (proprietary) RAR rar a -m5 -md64m -mc63:128t -mt1 8710 bytes -1282 bytes (-12.83%)
Brotli (Wikipedia) brotli brotli -q 11 9022 bytes -970 bytes (-9.71%)
ZPAQ (Wikipedia) zpaq zpaq -method 69 9329 bytes -663 bytes (-6.64%)
PPMd (Wikipedia) 7zip 7za a -mx=9 -m0=ppmd 9526 bytes -466 bytes (-4.66%)
Burrows-Wheeler transform (Wikipedia) bzip2 bzip2 -9 9845 bytes -147 bytes (-1.47%)
LZMA2 (Wikipedia) xz xz -9 9912 bytes -80 bytes (-0.80%)
ZSTD (Wikipedia) zstd zstd -19 10000 bytes +8 bytes (+0.08%)

Detailled Analysis

I wrote a DEFLATE decoder in Javascript. Click the button below to start a client-side analysis of the smallest gzipped files (may take a second):


Notes: pigz is a fast open source multi-threaded implementation of gzip written by one of the original authors of gzip.
However, when using compression level 11, pigz actually switches to the slower Zopfli algorithm and isn't multi-threaded anymore.
KrzyMOD's extensions to Zopfli offer the highest level of configuration and is therefore used for my brute-force search.
Ken Silverman wrote the closed-source KZIP compression program and Jonathon Fowler ported it to Linux.
Defluff was created by Joachim Henke; DeflOpt is a tool by Ben Jos Walbeehm.

website made by Stephan Brumme in 2015 and still improving in 2018.
all timestamps are displayed in central european time. see my changelog.
no flash, not even images or external css files - and everything squeezed into a single html file.
which was handsomely compressed before releasing it into the wild internet - obviously.

please visit my homepage and my blog, too.
email: minime (at) stephan-brumme.com