Type Safety and Compilation Checks: How Static Analysis Can Benefit Your Team

Numerous technologies exist for creating web applications, with PHP and JavaScript being the most prevalent. Their dynamic typing and runtime execution capabilities allow for a seamless transition from prototype to finished product. However, as apps grow in complexity and significance in our everyday lives, the absence of type safety and compilation checks might be felt. In this presentation, we will explore the concept of static analysis and its potential to enhance your team's software development process.

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1. Type Safety and Compilation Checks: How Static Analysis Can Benefit Your Team
2. What is dynamic typing?
3. function createUser($name, $age) { // Other complex business logic return new User($name, $age) }
4. createUser('Hunter', 30); createUser('Joe', '24'); createUser('Franke', true); createUser(42, 'age');
5. var_dump(createUser('Franke', true)); => User {#2674 +name: "Franke", +age: 1, } var_dump(createUser(42, 'age)); => User {#2670 +name: "42", +age: 0, }
6. console.log(3 < 2 < 1); // true (huh?) console.log(false < 1);
7. How do we catch these types of bugs?
8. Static Analysis
9. Ok great, but how?
10. PHPStan
13. Psalm
17. Other cool features Security Analysis – Code Manipulation –
18. ------ ------------------------------------------------------ ------------------------------------------------------------- ------------------- Line ValueObjects/PhoneIntelligence.php ------ ----------------------------------------------------- ------------------------------------------------------------- -------------------- 45 Parameter $lineType of class App\ValueObjects\PhoneIntelligence constructor expects App\Enum\LineType, App\Enum\LineType|null given. 79 Method App\ValueObjects\PhoneIntelligence::toJson() should return string but returns string|false. ------ ----------------------------------------------------- ------------------------------------------------------------- --------------------
19. <?php declare(strict_types=1); namespace App\ValueObjects; class PhoneIntelligence implements Arrayable, Castable, Jsonable { public function __construct( private readonly ?string $formatted, private readonly ?string $carrier, private readonly LineType $lineType = LineType::Unknown ) { } public static function castUsing(array $arguments): CastsAttributes { return new class implements CastsAttributes { public function get($model, string $key, $value, array $attributes): PhoneIntelligence { return new PhoneIntelligence( formatted: $attributes['phone_formatted'], carrier: $attributes['phone_carrier'], lineType: LineType::tryFrom($attributes['phone_type'] ?? 'unknown'), ); } }; } public function toJson($options = 0) { return json_encode($this->toArray(), $options); } }
20. <?php declare(strict_types=1); namespace App\ValueObjects; class PhoneIntelligence implements Arrayable, Castable, Jsonable { public function __construct( private readonly ?string $formatted, private readonly ?string $carrier, private readonly LineType $lineType = LineType::Unknown ) { } public static function castUsing(array $arguments): CastsAttributes { return new class implements CastsAttributes { public function get($model, string $key, $value, array $attributes): PhoneIntelligence { return new PhoneIntelligence( formatted: $attributes['phone_formatted'], carrier: $attributes['phone_carrier'], lineType: LineType::from($attributes['phone_type'] ?? 'unknown'), ); } }; } public function toJson($options = 0) { return json_encode($this->toArray(), JSON_THROW_ON_ERROR | $options); } }
22. What about frontend development?
23. Introducing: TypeScript
24. TypeWhat?
29. interface Account { id: number displayName: string version: 1 } function welcome(user: Account) { console.log(user.id) } type Result = "pass" | "fail" function verify(result: Result) { if (result === "pass") { console.log("Passed") } else { console.log("Failed") } }
30. So how can we use these tools?
31. composer require --dev phpstan/phpstan composer require --dev vimeo/psalm
32. - run: name: "Perform a static analysis of application" command: | set -x git diff origin/master... > ~/test-results/phpstan/diff.txt if [ ! -s ~/test-results/phpstan/files.txt ]; then exit 0 fi docker compose run --rm app ./vendor/bin/phpstan analyse \ --memory-limit=-1 --error-format=junit --no-interaction --no-progress --no-ansi 1> ~/test-results/phpstan/junit.xml || true docker compose run --rm app ./vendor/bin/phpstan analyse \ --memory-limit=-1 --no-interaction --no-progress --no-ansi > ~/test- results/phpstan/phpstan.txt docker compose run --rm -v ~/test-results/phpstan:/test-reports app ./vendor/bin/diffFilter \ --phpstan /test-reports/diff.txt /test-reports/phpstan.txt 100
33. npm i typescript import axios, {AxiosResponse, AxiosStatic} from 'axios'; import {API_DOMAIN} from './constants'; import {Homeowner} from './homeowner'; import {Project} from './project'; import Contractor from './contractor'; import ExternalMatch from './external-match'; import {parse} from 'date-fns'; import * as _ from 'lodash'; class ModernizeClient { private axios: AxiosStatic; constructor() { this.axios = axios; this.axios.defaults.baseURL = API_DOMAIN; } public projectDetails(projectId: string): Promise<Project> { return axios.get('/v1/projects/' + projectId) .then(response => { let responseData = response.data.data; let homeowner = new Homeowner(responseData.homeowner.data.firstName, responseData.homeowner.data.lastName, responseData.homeowner.data.phoneNumber); return Promise.resolve( new Project(homeowner, responseData.projectType, parse(responseData.dateCreated), parse(responseData.startDate)) ); }); } } export {ModernizeClient}
34. ESLint npm install --save-dev eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin eslint . --ext .ts { "root": true, "parser": "@typescript- eslint/parser", "plugins": [ "@typescript-eslint" ], "extends": [ "eslint:recommended", "plugin:@typescript- eslint/eslint-recommended", "plugin:@typescript- eslint/recommended" ] }
35. WHAT ABOUT EXISTING PROJECTS?
36. PHP PHPStan vendor/bin/phpstan analyse -- level 9 \ --configuration phpstan.neon \ src/ tests/ --generate-baseline Psalm vendor/bin/psalm --set- baseline=your-baseline.xml vendor/bin/psalm --update- baseline Configuration includes: - phpstan-baseline.neon parameters: # your usual configuration options <?xml version="1.0"?> <psalm ... errorBaseline="./path/to/your- baseline.xml" > ... </psalm>
37. JavaScript TypeScript
38. { "compilerOptions": { "target": "esnext", "module": "commonjs", "allowJs": true, "checkJs": false, "outDir": "dist", "rootDir": ".", "strict": false, "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */, "forceConsistentCasingInFileNames": true, /* Disallow inconsistently-cased references to the same file. */ "declaration": true, /* Generates corresponding '.d.ts' file. */ "strictNullChecks": true, "resolveJsonModule": true, "sourceMap": true, "baseUrl": ".", "paths": { "*": [ "*", "src/*", "src/setup/*", "src/logic/*", "src/models/*", "config/*" ] }, }, "exclude": ["node_modules", "dist"], "include": [ "./src", "./test", "./*", "./config" ] }
39. /node_modules/typescript/bin/tsc
40. Closing Time
41. I've been: Hunter Skrasek
42. Where do I reside? Mastodon: hunter@social.skrasek.us Email: hskrasek@gmail.com
43. Questions?