kselax

// The sum of a range
// The introduction of this book alluded to the following as a nice way to compute
// the sum of a range of numbers:
// console.log(sum(range(1, 10)));
// Write a range function that takes two arguments, start and end , and returns
// an array containing all the numbers from start up to (and including) end .
// Next, write a sum function that takes an array of numbers and returns the
// sum of these numbers. Run the example program and see whether it does
// indeed return 55.
// As a bonus assignment, modify your range function to take an optional third

kselax

// Minimum
// The previous chapter introduced the standard function Math.min that returns
// its smallest argument. We can build something like that now. Write a function
// min that takes two arguments and returns their minimum.

let minimum = (a, b) => {
  if (a < b) {
    return a
  }
  return b

kselax

function findSolution(target) {
  function find(current, history) {
    if (current == target) {
      return history;
    } else if (current > target) {
      return null
    } else {
      return find(current + 5, `(${history} + 5)`) ||
             find(current * 3, `(${history} * 3`)
    }

kselax

{
  var x = 1
  {
    let x = 2 // SyntaxError: Identifier 'x' has already been declared
    {
      function f(){
        let x = 10
        {
          var x = 20 // SyntaxError: Identifier 'x' has already been declared
          {

kselax

{
  let x = 1
  {
    var x = 2 // SyntaxError: Identifier 'x' has already been declared
    {
      console.log('scope1 x = ', x);
    }
    console.log('scope2 x = ', x);
  }
  console.log('scope3 x = ', x);

kselax

{ 
  var x = 11
  {
    let x = 10
    {
      console.log('x (unknown) = ', x); // can you guess which x here?
      function f() {
        var a = 1
        {
          var a = 2

kselax

{ 
  var x = 11
  {
    var x = 10
    {
      function f() {
        var a = 1
        {
          var a = 2
          {

kselax

{ 
  var x = 11
  {
    var x = 10
    {
      var x = 30;
    }
    console.log('x = ', x); // 30
  }
  console.log('x = ', x); // 30

kselax

class MemDbKeyStore {
  constructor(name, store, initFn) {
    this.name = name
    this.store = store
    this.store[name] = {}

    if (typeof initFn === 'function') {
      initFn.call(this)
    } 
  }

kselax

'use strict'

const fs = require('fs')
const Table = require('./Table') // return class Table
const Log = require('../../model/Log') // return call Log

class DB {
  constructor() {
    this.pool = null
    this.tablesNameArray = []