JonathonAshworth

// jdn conversions for date arithmetic/comparison
const intDiv = (l,r) => ~~(l/r); // integer division

const jdnFromIso = iso => {
  const [y, m, d] = iso.split('-').map(s => parseInt(s, 10));
  return intDiv(1461 * (y + 4800 + intDiv(m - 14, 12)), 4)
    + intDiv(367 * (m - 2 - 12 * intDiv(m - 14, 12)), 12)
    - intDiv(3 * intDiv(y + 4900 + intDiv(m - 14, 12), 100), 4)
    + d - 32075;
};

JonathonAshworth

useEffect(() => {
  const pFoo = getFoo().then(foo => /* do somthing with our async foo, making sure to return it */);
  return () => pFoo.then(foo => /* cleanup here will always run after we have gotten our foo and used it */);
});

// This is one of the few cases where it makes sense to use raw promises instead of async/await
// The power of promises is that you can compose asynchronous logic asynchronously
// Afaik that's not possible with async/await?

JonathonAshworth

// f of the form v => v
export const objMap = (obj, f) =>
  Object.fromEntries(Object.entries(obj).map(([k, v]) => [k, f(v)]));

// f of the form ([k, v]) => [k, v]
export const objMapEntries = (obj, f) =>
  Object.fromEntries(Object.entries(obj).map(f));

export const arrDeepMap = (arr, f) => arr.map((x, i, a) => Array.isArray(x) ? arrDeepMap(x, f) : f(x, i, a));

JonathonAshworth

// f of the form (k, v) => v
export const objMap = (obj, f) =>
  Object.fromEntries(Object.entries(obj).map(([k, v]) => [k, f(k, v)]));

// f of the form ([k, v]) => [k, v]
export const objMapEntries = (obj, f) =>
  Object.fromEntries(Object.entries(obj).map(f));

JonathonAshworth

export default async n => new Promise((res, rej) => window.setTimeout(() => res(), n))

JonathonAshworth

export const debounce = (f, delay) => {
  let timer = null

  return (...args) => {
    const execute = () => {
      timer = null
      f(...args)
    }

    if (timer !== null)

JonathonAshworth

export const unique = (arr, eq) => arr.reduce(
  (acc, item) => (eq ? acc.find(a => eq(a, item)) !== undefined : acc.includes(item))
    ? acc
    : [...acc, item]
, [])

JonathonAshworth

const imSet = (objOrArray, path, valueOrFunc) => {
  const multipath = Array.isArray(path) && path.length > 1
  const pathItem = Array.isArray(path) ? path[0] : path // unwrap single item array
  const isFunc = typeof valueOrFunc === "function"

  const value = multipath
    ? imSet(objOrArray[pathItem], path.slice(1), valueOrFunc)
    : isFunc ? valueOrFunc(objOrArray[pathItem]) : valueOrFunc

  if (Array.isArray(objOrArray)) {

JonathonAshworth

class FooPage {
  
  async loadData () {
    const data = await getData()
    this.setState({ data })
  }
  
  render () {
    return (
      <Page data={this.state.data} loadData={this.loadData}>

JonathonAshworth

const data = {
  people: [
    {
      id: 0,
      name: 'John',
      bankAccount: { id: 0, balance: 2864 },
      address: { id: 0, number: 83, street: 'Foo St' },
    },
    {
      id: 1,