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
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// 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 |
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| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
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| 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
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| 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 |
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| 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 |
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| 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
