christophemarois

import { orderBy } from 'lodash'

function chain<OriginalValue>(originalValue?: OriginalValue) {
  let fns: Array<(val: any) => any> = []

  function step<CurrentValue>(currentValue: CurrentValue) {
    const methods = {
      do<NextValue>(fn: (val: CurrentValue) => NextValue) {
        fns.push(fn)
        return step<Awaited<NextValue>>(

christophemarois

# Install brew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Install nvm
brew install nvm

# Install node 18
nvm install node 18
nvm alias default node 18

christophemarois

export class ResponseNotOkError extends Error {
  constructor(public response: Response) {
    super(`HTTP ${response.status}`)
    
    // These lines can be added to further mimic Error magic properties.
    // Never needed them, though.
    this.name = this.constructor.name
    Object.setPrototypeOf(this, ResponseNotOkError.prototype)
  }
}

christophemarois

interface Serializable {
  toString: () => string;
}

function groupBy<T>(els: T[], fn: (el: T) => Serializable) {
  let out: Record<string, T[]> = {};

  for (const el of els) {
    const k = fn(el).toString();
    

christophemarois

/*
My answer to a technical JS question: build your own Promise.all

I decided to build my implementation, diyPromiseAll, using typescript
and to ensure that all type signatures are the same as the real Promise.all
of lib.es2015.

Following spec, diyPromiseAll:
- accepts any iterable of values of known or unknown size
- accepts values of mixed promises and non-promises (and thus nested instances of itself)

christophemarois

import fs from 'node:fs'

export function fsReadLinesIterator(filepath: string, chunkSize: number) {
  return {
    async *[Symbol.asyncIterator](): AsyncGenerator<string> {
      let line = ''

      // Read utf8 chars in chunks of chunkSize
      const stream = fs.createReadStream(filepath, {
        highWaterMark: chunkSize,

christophemarois

class ArticleManager {
  urls: string[] = []

  async *[Symbol.asyncIterator](): AsyncGenerator<[string, string]> {
    for (const url of this.urls) {
      const html = await fetch(url).then(resp => resp.text())
      yield [url, html]
    }
  }
}

christophemarois

function padToFit(x: number, target: number) {
  const pad =
    Math.floor(Math.log10(Math.max(1, Math.floor(Math.abs(target))))) + 1
  return x.toFixed(0).padStart(pad, '0')
}

padToFit(4, 9827) // => 0004
padToFit(4, 22) // => 04

christophemarois

#!/usr/bin/env -S npx ts-node --transpile-only
console.log('hi' as string)

christophemarois

const fractionalExp = /(?:(?:(\d+)\s+)?(\d)\/(\d))/
const floatExp = /(\d+(?:\.\d+)?)/
const matcherExp = new RegExp(
  `(${fractionalExp.source}|${floatExp.source})`,
  'g'
)

function transformAmounts(str, fn) {
  return str.replace(matcherExp, (part) => {
    const fractionalMatch = part.match(fractionalExp)