Jarrod Overson - @jsoverson
Achieving
Maintainability

a. k. a.

Idiot proofing your code

( psst, we’re all idiots )

We do stuff like…
❯ pi
3.141592653589793
❯ pi(2)
6.283185307179586

Or…
❯ 4..Days()
345600000
❯ 60..Seconds()
60000

And even…
<script src="#"></script>

What was clever six months agoclever

Is idiotic todayidiotic

We’re not awful people

We’re just smart

We’re just lazy
smart

We’re just
lazy
smart
bored

We’re just
lazy
smart
bored
evil

We’re just doing our job

And our job is hard

How do we get better at it?

EXAMINE1
2
3

How much analysis do you run on your code?

It’s not enough.

KNOW YOUR LINTERS
JSHINT
ESLINT
JSCS
Community-driven JSLint fork. High configurability.
JSHint alternative. High configurability.
Code style checker. Separate and complementary.
WHAT ABOUT JSLINT AND CLOSURE LINTER?

KNOW YOUR LINTER’S OPTIONS

"maxparams" : 4
"maxdepth" : 4
"maxstatements" : 20
"maxlen" : 100
"maxcomplexity" : 7
SET NUMERIC LIMITS

WHAT IS CYCLOMATIC COMPLEXITY?

CYCLOMATIC COMPLEXITY
IS THE NUMBER OF PATHS
THROUGH YOUR CODE
TECHNICALLY

CYCLOMATIC COMPLEXITY
IS HOW HARD
YOUR CODE IS TO TEST
PRACTICALLY

!
function main(a) {
!
}
COMPLEXITY : 1

function main(a) {
if (a > 5) {
}
}
COMPLEXITY : 2

function main(a) {
if (a > 5) {
!
} else {
!
}
}
COMPLEXITY : ?

function main(a) {
if (a > 10) {
!
} else if(a > 5) {
!
}
}
COMPLEXITY : 3

function main(a) {
if (a > 5) {
if (a > 10) {
!
}
}
}
COMPLEXITY : 3

function main(a) {
if (a) {
} else if (a) {
}
!
if (other) { }
!
for (var i = 0; i < a; i++) {
if (i % 2) {
} else if (i % 3) {
}
}
}
COMPLEXITY : 7

GENERATE VISUAL REPORTS

code coverage
istanbul
jscover
blanket

plato
complexity
maintainability
lint errors

MAINTAINABILITY?
fn(averageEffort, averageComplexity, averageLines);
fn(difficulty, volume)
fn(length, vocabulary)
fn(uniqueOperators, totalOperands, uniqueOperands)
fn(uniqueOperators, uniqueOperands)
fn(totalOperators, totalOperands)

doc coverage
this
exist
doesn’t

AUTOMATE2
3
1

IF IT’S NOT EASY
It won’t be done
IF IT’S NOT AUTOMATED
It will only get done once.
IF IT’S NOT VISUALIZED
It might as well not be done at all

Build first
Before you write code, set up your build

But that’s annoying!

Look into yeoman
Manages file copies, conflicts, prompts, defaults

But I don’t want to learn Yeoman!

$ npm install yo generator-generator
!
$ mkdir generator-myWorkflow
!
$ cd generator-myWorkflow
!
$ yo generator

But I don’t need all that!

Delete, add, and modify
It’s surprisingly easy.

Grunt VS Gulp
it doesn’t matter, just choose one.

What about…
• MAKE
• RAKE
• JAKE
• ANT
• BROCCOLI
• blahhhh…

it doesn’t matter
just choose one.
( but be ready to support it )

Want code coverage?
grunt-contrib-jasmine
grunt-mocha-istanbul
grunt-jscoverage
and 30 more

Want linting?
grunt-contrib-jshint
grunt-eslint
grunt-jscs-checker
and 50 more

Want docs?
grunt-contrib-yuidoc
grunt-jsdoc
grunt-docco
and 90+ more

There’s no excuse
for manual process

PROTECT3
1
2

‣ Code style
‣ Metrics
‣ Build tools
‣ Data formats
‣ Naming conventions
‣ Curly Braces
‣ Directory structure
‣ Everything
ENFORCE
‣ Automate Everything
‣ VCS hooks
‣ CI
‣ Code reviews
‣ Reports
‣ Everything
‣ Warnings === errors
‣ Make it hard to be
wrong
DOCUMENT
‣ Treat docs as code
‣ Make it
‣ easy to find
‣ easy to read
‣ easy to update
‣ easy to discuss
‣ Use github!
AGREE
GET EVERYONE TOGETHER

Your automation choice needs to
accommodate enforcement

Recap
your analysis
your enforcement
your everything
Automate
Automate
Automate

Jarrod Overson - @jsoverson
Achieving
Maintainability