aiya000

const chars = [
  '亜',
  '哀',
  '挨',
  '愛',
  '曖',
  '悪',
  '握',
  '圧',
  '扱',

aiya000

#!/bin/bash
negative_state=$(cat <<- END
	{
		"state": "failure",
		"context": "poi",
		"description": "hi"
	}
	END
)
echo "$negative_state"

aiya000

module.exports = {
  trailingComma: 'all',
  tabWidth: 2,
  semi: false,
  singleQuote: true,
  printWidth: 100,
}

aiya000

module.exports = {
  root: true,
  env: {
    browser: true,
    node: true,
  },
  extends: [
    '@nuxtjs/eslint-config-typescript',
    '@vue/prettier',
    '@vue/prettier/@typescript-eslint',

aiya000

const x: { x: number } | null = { x: 10 }
console.log(x.x) // no errors

const y: { x: number } | null = null
console.log(y.x) // 2531: Object is possibly 'null'.

aiya000

/**
 * The type 'true' means a proof is satisfied.
 * The type 'never' means a proof is not satisfied.
 */

// Basic of this idea.

type AWrongProof = { x: number } extends { x: string } ? true : never

// Compile NG

aiya000

/**
 * Proves that A and B is the same types.
 */
export type Equal<A, B> = A extends B ? (B extends A ? true : never) : never

/**
 * Makes all fields of A to `<its-type> | null`.
 */
export type Nullable<A extends Record<string, unknown>> = { [K in keyof A]: A[K] | null }

aiya000

/**
 * Proves that A and B is the same types.
 */
export type Equal<A, B> = A extends B ? (B extends A ? true : never) : never

/**
 * Makes all fields of A to `<its-type> | null`.
 */
export type Nullable<A extends Record<string, unknown>> = { [K in keyof A]: A[K] | null }

aiya000

import axios from 'axios'

function isThatArray<T>(x: unknown, p: (a: unknown) => a is T): x is Array<T> {
  return Array.isArray(x) && x.every(p)
}

function isString(x: unknown): x is string {
  return typeof x === 'string'
}

aiya000

{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE FlexibleInstances #-}

newtype Fix f = Fix
  { unFix :: f (Fix f)
  }

cata :: Functor f => (f a -> a) -> Fix f -> a
cata f (Fix x) = f $ fmap (cata f) x