gchumillas

import { useCallback, useMemo, useEffect } from 'react'

export const useBreakpoints = <T extends Record<string, number>>(breakpoints: T): keyof T | undefined => {
  const searchBreakpoint = useCallback((breakpoints: { key: string, value: number }[]) => {
    return breakpoints.find((x) => window.innerWidth < x.value)?.key
  }, [])

  const entries = useMemo(() => {
    return Object
      .entries(breakpoints)

gchumillas

import { useCallback, useMemo, useState } from 'react';

const useValidator = <T extends Record<string, string>>(validator: () => T) => {
  const [errors, setErrors] = useState<Partial<T>>({})

  return useMemo(() => ({
    validate: () => {
      setErrors(validator())
      return Object.values(errors).every((x) => !x)
    },

gchumillas

extension Array where Element: Collection {
    // Calculates the size of a matrix.
    func size() -> (cols: Int, rows: Int) {
        let numRows = self.count
        let numCols = self.reduce(0, { Swift.max($0, $1.count) })
        return (numCols, numRows)
    }

    // Transposes a matrix.
    //

gchumillas

extension String {
    func leftTrimmed() -> Self {
        guard let i = self.firstIndex(where: { !$0.isWhitespace }) else {
            return ""
        }
        return "\(self[i...])"
    }

    func rightTrimmed() -> Self {
        guard let i = self.lastIndex(where: { !$0.isWhitespace }) else {

gchumillas

extension String {
  func chunks(_ size: Int) -> [String] {
    stride(from: 0, to: self.count, by: size).map {
      let i0 = self.index(self.startIndex, offsetBy: $0)
      let i1 = self.index(self.startIndex, offsetBy: min($0 + size, self.count))
      return "\(self[i0..<i1])"
    }
  }
}

gchumillas

import { Db } from 'mongodb'

// Increments the `count` field of the `codes` collection and returns it.
// This function is "thread safety".
//
// It's important to update and find the document at the same time.
// Otherwise a "race condition" may arise.
const newCode = async (db: Db, name: string) => {
  const { value: { count } } = await db.collection('codes').findOneAndUpdate({ name }, { $inc: { count: 1 } }, {
    upsert: true,

gchumillas

/**
 * Sorts a list list of records by fields.
 * 
 * 
 * Example 1:
 * 
 * const items = [
 *   { currency: 'EUR', amount: 101.45 },
 *   { currency: 'EUR', amount: 33.23 },
 *   { currency: 'EUR', amount: 55.00 },

gchumillas

/**
 * Picks a random item from a list.
 * 
 * For example:
 * 
 *    pick(['a', 'b', 'c'], [0.7, 0.2])
 *    // outputs 'a' with 70% chance
 *    // outputs 'b' with 20% chance
 *    // outputs 'c' with 10% chance (the rest)
 * 

gchumillas

A list of naming conventions based on this excelent article:
https://betterprogramming.pub/useful-tips-for-naming-your-variables-8139cc8d44b5

Naming numbers

Integer numbers

const somethingCount    // itemsCount (preferable)
const numberOfSomething // numberOfItems

gchumillas

import React from 'react'
import _ from 'lodash'

export type Validator = (val: any) => string | true

const useValidator = ({
  defaultValidator = () => true,
  validators
}: {
  defaultValidator?: Validator