gvergnaud

import { arg0, Call, Constant, Eval, Fn, Objects, Tuples } from "../src/index";

type Ok<A> = { tag: "Ok"; value: A };

type Err<B> = { tag: "Err"; value: B };

type Result<A, B> = Ok<A> | Err<B>;

type ParseError<expected = unknown, encountered = unknown> = {
  expected: expected;

gvergnaud

type MergeParameters3<T extends readonly UnknownFunction[]> = H.Pipe<
  T,
  [
    H.Let<"parametersList", H.Tuples.Map<H.Functions.Parameters>>,
    H.Let<
      "longestLength",
      H.ComposeLeft<
        [
          H.Get<"parametersList">,
          H.Tuples.Map<H.Tuples.Length>,

gvergnaud

// a conditional type is just type-level code branching

// A extends B means "A is assignable to B"

type Test1 = "hello" extends string ? true : false;
//     ^?

type Test2 = 2 extends string ? true : false;
//     ^?

gvergnaud

// mapped type version
type Fn<T> = {
  [K in keyof T]: [K, T[K]] /* arbitrary fn using K and T[k]  */;
};

// distributive union version
type Fn2<T> = FromEntries<
  keyof T extends infer K
    ? K extends keyof T
      ? [K, [K, T[K]] /* arbitrary fn using K and T[k]  */]

gvergnaud

import type { Equal, Expect } from '@type-challenges/utils'

type Assign<A, B> = {
    [K in keyof A | keyof B]: K extends keyof B
        ? B[K]
        : K extends keyof A
        ? A[K]
        : never;
}

gvergnaud

  type Range<n, range extends any[] = []> =
    range['length'] extends n ? range : Range<n, [...range, range['length']]>
  
  type Drop1<a extends any[]> =
    a extends [...infer inits, any] ? inits : []
  
  type Concat<a extends any[], b extends any[]> = [...a, ...b]
  
  type Plus<a, b> =
    [...Range<a>, ...Range<b>]['length']

gvergnaud

export type TaskPriority = "user-blocking" | "user-visible" | "background";

export type SchedulerPostTaskOptions = {
  // This priority is immutable and overrides the
  // TaskController's priority.
  priority?: TaskPriority;
  delay?: number;
  signal?: TaskSignal;
};

gvergnaud

type TupleToList<xs> = xs extends [infer head, ...(infer tail)]
  ? [head extends any[] ? head[number] : never, ...TupleToList<tail>]
  : [];

  
  
function permute<xs extends [] | [any[], ...any[][]]>([
  head,
  ...rest
]: xs): TupleToList<xs>[];

gvergnaud

const fs = require("fs");

const tasks = JSON.parse(fs.readFileSync("./input-5req-2render-slow.json"));

// Build histogram of tasks with buckets of 1000ms
const histogram = tasks.reduce((acc, task) => {
  const key = Math.floor(task.start / 1000) + "";
  return Object.assign(acc, {
    [key]: (acc[key] ?? []).concat(task),
  });

gvergnaud

/**
 * We call "variance" the direction of assignability between two types
 * (in other words, which type is a subtype of the other).
 * 
 * The same type can have a different variance in function of his position
 * in a larger type, and this is what makes assignability in TypeScript
 * not always straightforwards.
 * 
 * There are 4 kinds of variance: 
 * - Covariant: if the type `a` is assignable to `a | b`.