jlongster

// This function:

function foo() {
  var x = 5;
  var y = 6;
  debugger;
  return x + y;
}

jlongster

;; outlet code for implementing traditional macro expansion

;; macros

(define (expand form)
  (cond
   ((variable? form) form)
   ((literal? form) form)
   ((macro? (car form))
    (expand ((macro-function (car form)) form)))

jlongster

(function() {
  // Do not use this library. This is just a fun example to prove a
  // point.
  
  var Bloop = window.Bloop = {};

  var mountId = 0;
  function newMountId() {
    return mountId++;
  }

jlongster

const React = require('react');
const ReactDOM = require('react-dom');

const dom = React.DOM;

const Circle = React.createClass({
  propTypes: {
    x: React.PropTypes.number,
    y: React.PropTypes.number,
    dt: React.PropTypes.number,

jlongster

;; outlet: https://github.com/jlongster/outlet


(define (atom? exp)
  (or (number? exp)
      (string? exp)
      (boolean? exp)
      (null? exp)
      (symbol? exp)))

jlongster

import { useLoaderData, Link, useSearchParams } from 'remix';
import { parseISO, format } from 'date-fns';
import groupBy from 'lodash/groupBy';

let PAGE_SIZE = 5;

function safeParseInt(str) {
  let parsed = parseInt(str);
  return isNaN(parsed) ? 0 : parsed;
}

jlongster

A lot of people mentioned other immutable JS libraries after reading my post. I thought it would be good to make a list of available ones.

There are two types of immutable libraries: simple helpers for copying JavaScript objects, and actual persistent data structure implementations. My post generally analyzed the tradeoffs between both kinds of libraries and everything applies to the below libraries in either category.

Libraries are sorted by github popularity.

Persistent Data Structures w/structural sharing

jlongster

import Timestamp from './timestamp';

function getKeys(trie) {
  return Object.keys(trie).filter(x => x !== 'hash');
}

function keyToTimestamp(key) {
  // 16 is the length of the base 3 value of the current time in
  // minutes. Ensure it's padded to create the full value
  let fullkey = key + '0'.repeat(16 - key.length);

jlongster

// UPDATE: don't use this. when it re-partitions the list when time moves forward, it does not correctly keep hashes
// Use a real merkle tree instead: https://gist.github.com/jlongster/f431b6d75ef29c1a2ed000715aef9c8c

import Timestamp from './timestamp';

// This is a compact data structure that keeps track of a list of
// hashes (representing messages) over a range of time in order to
// figure out what has changed between clients, kinda like a Merkle
// tree. It creates "buckets" that represent different time ranges,
// and divides time into smaller buckets the more recent they are. The

jlongster

3 Gripes With React

I started using React 3.5 years ago, and I still love it. It was such a well-designed solution that not much has changed since then, only superficial stuff like naming. What I learned then is still wholly applicable today because it's such a good idea (although now you can choose from many other libraries). On top of that, we now benefit from an entirely new architecture (fiber) without changing much.