lokshunhung

// A scratchpad testing the differences between:
// - `String.prototype.match` (with & without `g` flag)
// - `RegExp.prototype.exec`  (with & without `g` flag)

const str = "A string\nWith 2 endlines\n";

(function () {
  console.info("==== String.prototype.match GLOBAL ====");
  const re = /(\w)(?<NamedGroup1>\w)\n/g;
  // Returns an array containing **all** string segments matching the **whole regex**

lokshunhung

# 1) JS Types

There are 2 types in JS: **primitives** and **objects**.

## 1.1) Primitives

-   `undefined`
-   `null`
-   `boolean`
-   `number`

lokshunhung

function Animal(nickname, gender) {
    this.nickname = nickname;
    this.gender = gender;
}
Animal.prototype.getName = function () {
    return this.nickname;
};
Animal.prototype.getGender = function () {
    if (this.gender === "M") return "boy";
    if (this.gender === "F") return "girl";

lokshunhung

Hackweek - GoodTypes

Good TypeScript, but without the "Script" part.

lokshunhung

const validatorOptions: import("class-validator").ValidatorOptions = {
    //* do not include `target` and `value` when reporting error
    validationError: { target: false, value: false },

    //* unknown objects (aka not instance of decorated class) fails validation instead of passing
    //* https://github.com/typestack/class-validator/blob/c2f999f9cc7ee2f40749780a89ae9f1f59f0b3e1/src/validation/ValidationExecutor.ts#L65
    forbidUnknownValues: true,

    //* strips non-decorated properties (aka "whitelisted") on the object to-be-validated
    //* use `@Allow()` to "whitelist" a property if no decorators are appropriate

lokshunhung

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

• You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.

• Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

lokshunhung

import Foundation

@main struct FileScratch {
    static func main() {
        let fm: FileManager = .default
        let home: URL = fm.homeDirectoryForCurrentUser
        // Older API for `.appending(path:directoryHint:)`: `.appendingPathComponent(_:)`
        // https://developer.apple.com/documentation/foundation/url/1780239-appendingpathcomponent
        let outputFile = home
            .appending(path: "Desktop")

lokshunhung

import Foundation

// https://github.com/apple/swift/blob/main/include/swift/ABI/MetadataKind.def
struct MetadataKind: Equatable {
    var rawValue: UInt

    /// A class type.
    static var `class`: Self {
        .init(rawValue: 0) }
    /// A struct type.

lokshunhung

// consumeIterable.ts

type NoInfer<T> = [T][T extends any ? 0 : never]; // https://github.com/millsp/ts-toolbelt/blob/319e551/sources/Function/NoInfer.ts#L27
type AnyIteratorResult = IteratorResult<any, any>;

function consumeIterable<T>(
    producer: Iterable<T>,
    consumer: () => Generator<undefined, void, NoInfer<T>>
): void {
    const produce = producer[Symbol.iterator]();

lokshunhung

import Combine
import RxSwift

public final class RxCurrentValueSubject<Output, Failure: Error>: Combine.Subject {
    private let rxSubject: RxSwift.BehaviorSubject<Output>
    private let combineSubject: Combine.CurrentValueSubject<Output, Failure>

    private let disposeBag = RxSwift.DisposeBag()

    public init(rxSubject: RxSwift.BehaviorSubject<Output>) {