How to rest assured

couple of good practices

by @polishdeveloper

About me

@PolishDeveloper

Almost 10 years

CleanCode advocate

Racing is my love

When no one is looking I play Minecraft

Twitter:polishdeveloper

Skype:polishdeveloper

GitHub:polishdeveloper

M@ail: piotr@polishdeveloper.pl

Agenda

about me

why

be lazy

unit testing

don’t trust

use tools

estimations

Q\A

Why

Helping each other

It’s good to give

Giving a lecture makes you a better person,

really!

Be Lazy

"if something — anything — requires more than 90 seconds of his

time, he writes a script to automate that.”

- late at work

- automatic customer email

- send email to wife

- make coffee

http://www.businessinsider.com/programmer-automates-his-job-2015-11

Be Lazy

• If something requires more than one command or command has more than two params, write a script.

• If you do something often, automate it

• If you can tell computer to do something for you, do it (Hooks)

• Don’t ask me to think - consistent dictionary across team

• Don’t ask me to think 2 - charts and logs

• Create WIKI

Be lazy - npm scripts

"scripts": {

"postinstall": "./node_modules/.bin/typings install",

"build": "cross-env NODE_ENV=production webpack --config webpack/webpack-

production.config.js --progress --profile --colors",

"build:dev": "node webpack/dev-server.js",

"start": "concurrently \"npm run build\" \"node server/production\"",

"start:dev": "concurrently \"npm run build:dev\" \"node server/development\"",

"test": "tsc && mocha --require test-setup --recursive ./dist/**/__spec__/**/*-spec.js"

},

Be lazy - git hook

#!/usr/bin/env ruby

message_file = ARGV[0]

message = File.read(message_file)

$regex = /\[ref: (\d+)\]/

if !$regex.match(message)

puts "[POLICY] Your message is not formatted correctly"

exit 1

end

Be lazy but not too lazy

“There are two sides to every story”

JS won’t keep you lazy

console.log(1 + 1); // 2

console.log(1 + '1'); // '11'

console.log('1' + 1); // '11'

console.log('1' + '1'); // '11'

JS won’t keep you lazy

console.log(1 + 1); // 2

console.log(1 + '1'); // '11'

console.log('1' + 1); // '11'

console.log('1' + '1'); // '11'

console.log(1 - 1); // 0

console.log(1 - '1'); // 0

console.log('1' - 1); // 0

console.log('1' - '1'); // 0

JS won’t keep you lazy

console.log(1 + 1); // 2

console.log(1 + '1'); // '11'

console.log('1' + 1); // '11'

console.log('1' + '1'); // '11'

console.log(1 - 1); // 0

console.log(1 - '1'); // 0

console.log('1' - 1); // 0

console.log('1' - '1'); // 0

console.log('2' - '1' + '1'); // ??

console.log('2' - ('1' + '1')); // ??

JS won’t keep you lazy

console.log(1 + 1); // 2

console.log(1 + '1'); // '11'

console.log('1' + 1); // '11'

console.log('1' + '1'); // '11'

console.log(1 - 1); // 0

console.log(1 - '1'); // 0

console.log('1' - 1); // 0

console.log('1' - '1'); // 0

console.log('2' - '1' + '1'); // 11

console.log('2' - ('1' + '1')); // -9

JS is amazing

var x = {

empty1: '',

empty2: 0,

empty3: null,

empty4: undefined

};

console.debug(x.empty1 != false); // false

console.debug(x.empty2 != false); // false

console.debug(x.empty3 != false); // true

console.debug(x.empty4 != false); // true

console.debug(x.empty5 != false); // true

console.debug(x.hasOwnProperty('empty4')

&& x.empty4 != false);

Don’t trust - defensive programming

- Verify input

- Do not modify input

- Encapsulation everywhere

- Use const

It’s easy to make a typo

export class APIConnector {

public static OK = 'ok';

public static isSuccess(status:string) {

return status === APIConnector.OK;

}

}

Code should look like poem

export class Demo {

public static HAS_MORE_ITEMS = true;

public getMore(response:IArticlesResponse) {

return response.more == Demo.HAS_MORE_ITEMS

? this.fetchMore(response)

: [];

}

}

Unit test

const assert = require(‘chai').assert;

describe('Array', function() {

describe('#indexOf()', function() {

it('should return -1 when the value is not present’,

function() {

assert.equal(-1, [1,2,3].indexOf(5));

assert.equal(-1, [1,2,3].indexOf(0));

}

);

});

});

Don’t trust

if (_.get(x, 'schools.clasess[0].notebook', false) == false) {

// do something

}

Lazy people don’t trust(plus lazy people don’t want to think)

var hasNotebook = function(student) {

//assert that is proper student and has notebook

if (!_.has(student,“schools”) {

throw new Error("Schools property not found");

}

if (_.isEmpty(student.schools.classes)) {

throw new Error("User is not signed up to any class");

}

return _.first(student.schools.classes).notebook == false;

};

if (hasNotebook(student)) {

// do something

}

Keep things consistent

- Same dictionary

- Locked versions

- Docker/Vagrant as development container

Thing to remember

First write for humans,

then write for computers.

Tools

Tools - console has more to offer

console.log('test');

console.group('There are more');

console.debug('test');

console.info('test');

console.warn('test');

console.error('test');

console.groupEnd();

console.table([1,2,3]);

console.count();

console.trace('method');

Tools - console

Makefile is amazing

# development tasks, should be executed in your local env:

$ make run # runs the API via Docker Compose (for local dev)

$ make stop # stops the running containers

$ make image # builds a distribution Docker images

$ make push # pushes the Docker image to Docker Hub

$ make shell # Opens Docker container shell

# other tasks, should be executed in context of API container (see $ make

shell)

$ make install # installs all dependencies and prepares for development

$ make update # updates all dependencies and prepares for development

$ make migrate # migrates database to match the current mappings

$ make fixtures # loads fixtures into the database

$ make qa # runs QA tasks

$ make report # runs tests and generates code coverage report

3rd party APIs - MixPanel

<script type=“text/javascript">

mixpanel.track("Video played", {

"Video length": 213,

"id": "hY7gQr0"

});

</script>

3rd party APIs - TrackJS

<script type="text/javascript">

window._trackJs = { token: 'YOUR_TOKEN_HERE' };

</script>

<script

src=“//cdn.trackjs.com/releases/current/tracker.js">

</script>

Charts - why ?

Successful logins

Charts - why ?

Successful logins

Estimations

Create a WIKI

Q/A

Questions ???

Hugs time

Thank you!

\o/

Twitter:polishdeveloper

Skype:polishdeveloper

GitHub:polishdeveloper