Betterer

Incremental Improvement

December 2021

December 2021

Hi, I'm Craig!

December 2021

Legacy

December 2021

Local Maxima

Desired state

Current state

December 2021

Why don't we rewrite the whole thing?!

December 2021

Revolution!

December 2021

Revolution...

December 2021

Branching!

December 2021

Branching...

// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any
// eslint-disable-next-line @typescript-eslint/no-explicit-any

December 2021

Automation

December 2021

Humans

Not obsolete yet!

December 2021

Evolutionary Algorithms

December 2021

A genetic representation of the solution domain:

0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
1 0 1 0 1 0 1 0
0 1 1 0 0 0 0 1

0

Chromosome

Population

Gene

Genetic Algorithms

December 2021

A genetic representation of the solution domain:

A fitness function to evaluate the solution:

0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
1 0 1 0 1 0 1 0
0 1 1 0 0 0 0 1
f(chromosome) => score

Genetic Algorithms

December 2021

Termination

0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
1 0 1 0 1 0 1 0
0 1 1 0 0 0 0 1
1 0 1 0 1 0 1 0
0 1 1 0 0 0 0 1

Crossover

1 1 1 1 0 0 0 0
0 0 0 0 1 1 1 1

Offspring

0 0 0 0 1 1 1 0

Mutation

Genetic Algorithms

December 2021

Evolutionary Migration?

A fitness function to evaluate the solution:

f(codebase) => score

December 2021

Code as data

ts(codebase) => nCompilerErrors
eslint(codebase) => nLintErrors
axe(codebase) => nA11yErrors
jest(codebase) => coverage%

December 2021

f(oldScore, newScore) => better | worse | same

A comparison function to track progress:

Better?

f(codebase) => oldScore
f(codebase) => newScore

Old state of the codebase

New state of the codebase

December 2021

Codebase as database?

It has become common to store extra information about a codebase in the repository:

# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
# yarn lockfile v1

"@babel/code-frame@7.12.11":
  version "7.12.11"
  resolved "https://registry.npmjs.org/@babel/code-frame/-/code-...
  integrity sha512-Zt1yodBx1UcyiePMSkWnU4hPqhwq7hGi2nFL1LeA3EUl+...
  dependencies:
    "@babel/highlight" "^7.10.4"
// Jest Snapshot v1, https://goo.gl/fbAQLP
 
exports[`betterer should not stay worse if an update is forced 1`] = `
"// BETTERER RESULTS V2.
exports[\`tsquery no raw console.log\`] = { 
  ...
}
`

December 2021

Evolutionary Migration

A fitness function to evaluate the solution

A comparison function to track progress

A little file to store the results

December 2021

Betterer

Incremental Improvement

December 2021

December 2021

// package.json
{
  "name": "@craig/my-very-stable-package",
  "version": "20.2.1",
  "author": "Craig Spence <craigspence0@gmail.com>",
  "description": "Gee I wish this package was a little bit better.",
  "scripts": {
    "betterer": "betterer",
    // ...
  },
  // ...
  "devDependencies": {
    "@betterer/cli": "^5.0.0",
    // ...
  }
}

Initialising

December 2021

// .betterer.ts
export default {
  // Add tests here ☀️
};

Initialising

// .betterer.js
module.exports = {
  // Add tests here ☀️
}

TypeScript by default:

JavaScript if you're into that:

September 2021

December 2021

December 2021

My First Test

// .betterer.ts
import { BettererTest } from '@betterer/betterer';


export default {
  'migrate JS to TS': () => new BettererTest({
    // ...
  })
};

December 2021

My First Test

// .betterer.ts
import { BettererTest } from '@betterer/betterer';
import glob from 'glob';

export default {
  'migrate JS to TS': () => new BettererTest({
    test: () => glob.sync('**/*.js').length,
    // ...
  })
};

December 2021

My First Test

// .betterer.ts
import { BettererTest } from '@betterer/betterer';
import { smaller } from '@betterer/constraints';
import glob from 'glob';

export default {
  'migrate JS to TS': () => new BettererTest({
    test: () => glob.sync('**/*.js').length,
    constraint: smaller
  })
};

December 2021

December 2021

My First Result

// .betterer.results
// // BETTERER RESULTS V2.
exports[`migrate JS to TS`] = {
  value: `9`
};

This is basically the same things as a Jest snapshot file!

December 2021

December 2021

// cool.js
export function ohBoyILoveJavaScript () {
  console.log(`I'll never change!!!`);
  return [1, 2, 3] + [4, 5, 6];
}

December 2021

December 2021

My First  File Test

// .betterer.ts
import { BettererFileTest } from '@betterer/betterer';

export default {
  'migrate JS to TS': () =>
    new BettererFileTest(async (filePaths, fileTestResult) => {
      // ...
      // 
    }).include('**/*.js')
};

December 2021

My First  File Test

// .betterer.ts
import { BettererFileTest } from '@betterer/betterer';
import { promises as fs } from 'fs';

export default {
  'migrate JS to TS': () =>
    new BettererFileTest(async (filePaths, fileTestResult) => {
      await Promise.all(
        filePaths.map(async (filePath) => {
          const fileContents = await fs.readFile(filePath, 'utf8');
          const file = fileTestResult.addFile(filePath, fileContents);
          file.addIssue(0, 1, 'Please use TypeScript!');
        })
      );
    }).include('**/**/*.js')
};

December 2021

December 2021

// BETTERER RESULTS V2.
exports[`migrate JS to TS`] = {
  value: `{
    "index.js:2978447364": [
      [0, 0, 1, "Please use TypeScript!", "177600"]
    ],
    "cool.js:3542870298": [
      [0, 0, 1, "Please use TypeScript!", "287364"]
    ],
    "amazing.js:8762519887": [
      [0, 0, 1, "Please use TypeScript!", "726351"]
    ],
    //...
    // 9 total issues:
  }`
};

December 2021

December 2021

// BETTERER RESULTS V2.
exports[`migrate JS to TS`] = {
  value: `{
    "index.js:2978447364": [
      [0, 0, 1, "Please use TypeScript!", "177600"]
    ],
    "cool.js:3542870298": [
      [0, 0, 1, "Please use TypeScript!", "287364"]
    ],
    "amazing.js:8762519887": [
      [0, 0, 1, "Please use TypeScript!", "726351"]
    ],
    //...
    // 10 total issues:
  }`
};

December 2021

December 2021

December 2021

// BETTERER RESULTS V2.
exports[`migrate JS to TS`] = {
  value: `{
    "index.js:2978447364": [
      [0, 0, 1, "Please use TypeScript!", "177600"]
    ],
    "boo.js:1827649983": [
      [0, 0, 1, "Please use TypeScript!", "298736"]
    ],
    "gross.js:1872646688": [
      [0, 0, 1, "Please use TypeScript!", "009726"]
    ],
    //...
    // 8 total issues:
  }`
};

December 2021

More tests!

December 2021

Built in tests!

// .betterer.ts
import { angular } from '@betterer/angular';

import { eslint } from '@betterer/eslint';

import { regexp } from '@betterer/regexp';

import { stylelint } from '@betterer/stylelint';

import { tsquery } from '@betterer/tsquery';

import { typescript } from '@betterer/typescript';

December 2021

Betterer

Thanks!

December 2021

Betterer: Incremental Improvement - NG-BE

By Craig Spence

Betterer: Incremental Improvement - NG-BE

  • 824