mrjacobbloom

/**
 * A wrapper for async (probably mostly click) event handlers that disables the event target
 * until the handler resolves (or rejects). This prevents double-clicks/multiple submissions.
 * It sets target.disabled, but it could just as easily modify classNames or style.pointerEvents.
 *
 * @template {Event} E
 * @template Res
 * @param {(e: E) => Promise<Res>} callback - Async event handler to wrap
 * @returns {(e: E) => Promise<Res>} Wrapped event handler that automagically disables target
 *

mrjacobbloom

/**
 * React DevTools keeps not working for me lately. So here's a function that,
 * given a DOM element, finds its nearest ancestor component. Paste it into
 * the console and call `getParentComponent($1)`. It Probably only works when
 * React is in dev mode.
 *
 * @param {HTMLElement} elem - Input DOM element
 * @returns {import('react').ReactElement} Nearest parent component.
 */
const getParentComponent = (elem) => {

mrjacobbloom

/**
 * Here's a way to structure your Lox AST file in TypeScript that sidesteps code generation
 * (Lox is the language you build in "Crafting Interpreters" by Bob Nystrom)
 * Would it have been more TSy to have the AST nodes just be interfaces? Probably, but
 * I wanted to follow the book and its visitor pattern.
 */

export abstract class Expr {
  public accept<T>(visitor: ExprVisitor<T>): T {
    // Decide what the correct visitXExpr method name should be using the class's name

mrjacobbloom

/**
 * How to extend/augment the types for a 3rd-party TypeScript module. For example, if its DefinitelyTyped typings are incomplete.
 * (In most cases it's better to submit a pull request to DefinitelyTyped with the corrected types!)
 */

declare module 'quill' {
  const OrigQuill: typeof import('../../../node_modules/@types/quill').Quill;
  class Quill extends OrigQuill {
    // In this case, we're extending the type for the Quill class if it's using the "Bubble" theme
    public theme?: {

mrjacobbloom

/*
 * ELIZA
 * ELIZA is a simple chatbot developed in the 1960s that acts like a Rogerian psychotherapist
 * This is an attempt to port her into the TypeScript type system. By that, I mean all of the
 * logic for this chatbot exists in the "types" side of TypeScript and is removed when you
 * compile it to JavaScript. This is possible because TypeScript recently added very basic
 * support for parsing string literal types (see https://github.com/microsoft/TypeScript/pull/40336)
 * 
 * By Jacob Bloom @mrjacobbloom
 * Prompts and responses adapted from here: https://github.com/codeanticode/eliza/blob/master/data/eliza.script

mrjacobbloom

/**
 * Represents a value 0-1 inclusive. Just here to help me keep my math straight
 */
type Normalized = number & { __normalized__: undefined };
interface RGB { r: number; g: number; b: number; }

// CONTROLS

const TEXT = 'John Doe';
const FG_COLOR: RGB = { r: 72, g: 125, b: 175 }; // note: bg color should be #FFEADA

mrjacobbloom

// An implementation of arithmetic (well, of integer addition) in the TypeScript type system
// base-10 adaptation of this: https://blog.joshuakgoldberg.com/binary-arithmetic/
// note: this whole program is opposite endianness from the original article because Arabic numbers are RTL

type Digit = 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9;

/**
 * Our integer type, a tuple of digits with length 1-6
 * Note: for a simpler version with static-length Int, see the second revision of this gist
 */

mrjacobbloom

import * as React from 'react';
import { Form, FormControl } from 'react-bootstrap';

interface IMyComponentState = {
  foo: string;
  bar: string;
}

export class MyComponent extends React.Component<{}, IMyComponentState> {
  public state = {

mrjacobbloom

(Moved to https://github.com/mrjacobbloom/proposal-await-all)

A Syntax for Parallelism in ECMAScript: await.all {...}

This document proposes a new syntax for parallel promises in ECMAScript. Wherever await is available, the following syntax would also become available:

await.all {
  statement;
 statement;

mrjacobbloom

// Polyfill to add support for the global Undefined object to browsers that do not yet support it.
// Released into the public domain by Jacob Bloom

(() => {
  const global_ = typeof globalThis !== 'undefined' ? globalThis :
                  typeof self !== 'undefined' ? self :
                  typeof window !== 'undefined' ? window :
                  typeof global !== 'undefined' ? global : null;
  if (global_ === null) throw new Error('Cannot polyfill Undefined: unable to locate global object');
  if('Undefined' in global_) return;