A tool for reporting code complexity metrics in JavaScript projects. Currently the tool reports on:
- lines of code;
- cyclomatic complexity;
- Halstead metrics;
- maintainability index.
The tool can be configured to fail when complexity metrics pass a specified threshold, to aid its usefulness in automated environments / CI. There are also options for controlling how metrics are calculated and the format of the report output.
The metrics are calculated by walking syntax trees generated by the Esprima parser.
For people who are only interested in analysing small amounts of code and don't want to download the tool, there is also a web front-end available:
npm install complexity-report
sudo npm install -g complexity-report
cr [options] <file...>
The tool will recursively read files from any directories that it encounters automatically.
-o <file>
: Specify an output file for the report, defaults tostdout
.-f <format>
: Specify an output format for the report, defaults toplain
.-a
: Include hidden files in the report.-m <maintainability>
: Specify the per-module maintainability index threshold (beyond which, the process will fail when exiting).-c <complexity>
: Specify the per-function cyclomatic complexity threshold (beyond which, the process will fail when exiting).-d <difficulty>
: Specify the per-function Halstead difficulty threshold (beyond which, the process will fail when exiting).-v <volume>
: Specify the per-function Halstead volume threshold (beyond which, the process will fail when exiting).-e <effort>
: Specify the per-function Halstead effort threshold (beyond which, the process will fail when exiting).-s
: Silences the console output.-l
: Disregards operator||
as a source of cyclomatic complexity.-w
: Disregardsswitch
statements as a source of cyclomatic complexity.-i
: Treatsfor
...in
loops as a source of cyclomatic complexity.-t
: Treatscatch
clauses as a source of cyclomatic complexity.-n
: Uses the Microsoft-variant maintainability index.
Currently there are five output formats supported:
plain
,
markdown
,
minimal
,
json
and xml
.
These are loaded with require
from the src/formats
subdirectory
and adding new formats is really easy.
Each format module must export a function format
,
which takes a report object as its only argument
and returns its string representation of the report.
See src/formats/plain.js
for an example format.
var cr = require('complexity-report');
var report = cr.run(source, options);
The argument source
must be a string
containing the source code that is to be analysed.
The argument options
is an optional object
which may contain properties that modify
cyclomatic complexity calculation.
The following options are available:
logicalor
: Boolean indicating whether operator||
should be considered a source of cyclomatic complexity, defaults totrue
.switchcase
: Boolean indicating whetherswitch
statements should be considered a source of cyclomatic complexity, defaults totrue
.forin
: Boolean indicating whetherfor
...in
loops should be considered a source of cyclomatic complexity, defaults tofalse
.trycatch
: Boolean indicating whethercatch
clauses should be considered a source of cyclomatic complexity, defaults tofalse
.newmi
: Boolean indicating whether the maintainability index should be rebased on a scale from 0 to 100.
The returned report is an object that contains properties detailing the complexity of each function from the source code. There is also a maintainability index as well as aggregate complexity metrics for the source in its entirety.
Visualizations:
Build tools:
The short-term plan is to write more output formats and open up lots more options for external configuration of the analysis.
I also need to spend some time throwing more complex test cases at it, to flush out all of the edge cases that I'm probably not yet handling. To this end, it would be great to hear from people that have run the tool against their own codebases. The bigger and uglier, the better! If you spot any issues, please raise them in the tracker.
In the longer term, I have some vague ideas concerning how to track trends in a codebase over time. Visualisations is another area that could be pretty sweet to look into.
If you think there's anything else I should look at,
please raise an issue or, even better,
feel free to implement it and submit a pull request! :)
The build environment relies on
Node.js,
NPM,
Jake,
JSHint,
Mocha and
Chai.
Assuming that you already have Node.js and NPM set up,
you just need to run npm install
to install all of the dependencies
as listed in package.json
.
The tests are in test/complexityReport.js
. You can run them with the
command npm test
or jake test
.