fast-stable-stringify

Android 4.0 is marked failing because it is slower than substack's, not because it does not work. Click on the badge to inspect the test details.

The most popular repository providing this feature is substack's json-stable-stringify. The intent if this library is to provide a faster alternative for when performance is more important than features. It assumes you provide basic javascript values without circular references, and returns a non-indented string.

Usage:

var stringify = require('fast-stable-stringify');
stringify({ d: 0, c: 1, a: 2, b: 3, e: 4 }); // '{"a":2,"b":3,"c":1,"d":0,"e":4}'

Just like substack's, it does:

• handle all variations of all basic javascript values (number, string, boolean, array, object, null)
• handle undefined in the same way as JSON.stringify
• work without native JSON.strinxgify
• not support ie8 (and below) with complete certainty. At least, his build failed on ie8.

Unlike substack's, it does:

• not implement the 'replacer' or 'space' arguments of the JSON.stringify method
• not check for circular references
• not check for .toJSON() methods on objects

Test results

Tested validity (answer equal to substack's) and benchmark (faster than substack's). A test passes only if it has the same output as substack's but is faster (as concluded by benchmark.js).

To (hopefully) prevent certain smart browsers from concluding the stringification is not necessary because it is never used anywhere, I summed up all the lengths of the resulting strings of each benchmark contestant and printed it along with the result data.

* I did (nickyout / substack) - 1 in percentages

Looks like it's generally faster. I would say about 50% in practice since chrome-ff-ie take the brunt of the used browsers (or see caniuse browser usage).

See ./results.txt for the original output.

Also

It exposes the way strings are escaped for JSON:

var stringify = require('./'),
    stringSearch = stringify.stringSearch,
    stringReplace = stringify.stringReplace,
    str = "ay\nb0ss";
str.replace(stringSearch, stringReplace); // 'ay\\nb0ss'

It does NOT add the quotes before and after the string needed for JSON.stringify-ing strings. Fortunately, that isn't hard:

'"' + str.replace(stringSearch, stringReplace) + '"'; // '"ay\\nb0ss"'

Running tests

For testing in node, do:

npm test

I used zuul for testing on saucelabs. It's a very easy to use tool, but because their library is about 150MB I did not include it in the devDepencencies. I suggest installing it globally if you want to test:

# install zuul
npm install -g zuul
# then, to run all tests
zuul -- test/index.js

TODO

• Travis
• Coverage