为什么我的外部变量在使用 while 循环时不会改变？

Question

function ranNum(value) {
  return Math.ceil(Math.random() * value)
}

function createRanId(value) {
  const alphabet = 'abcdefghijklmnopqrstuvwxyz'.split('')
  const numbers = '0123456789'.split('')
  const idLength = value || 6
  let id = ''

  for(let i = 0; i < idLength; i++) {
    const numOrAlpha = ranNum(2)

    numOrAlpha === 1 ? id += alphabet[ranNum(alphabet.length - 1)] : id += numbers[ranNum(numbers.length - 1)]
  }

  return id
}

function isAllNumbers(arr) {
  return arr.every(value => Number.isInteger(value))
}

function allNumberId() {
  let count = 0
  let ranNum = createRanId(2).split("");

  while(!isAllNumbers(ranNum)) {
    ranNum = createRanId(2).split("")
    count++
  } 


  return [count, ranNum]
}

console.log(allNumberId())

So what im doing is generating a random string that consists of numbers and letters (for example: 3e3jjf). What i'm trying to achieve is to find a generated combination that only consists of numbers (for example: 235033). However, my code doesnt seem to work and ends up in an infinite loop. I'm making a thinking error somewhere in the function allNumberId

edit: this is obviously not production code or anything. I'm just practicing some javascript. It bugs me that I cant find what I do wrong here.

Answer 1

In your code you are checking for a number

Number.isInteger("6")

When it is a string it is false. So you need to alter your code to try to make it into a number or other option is isNaN()

 function ranNum(value) { return Math.ceil(Math.random() * value) } function createRanId(value) { const alphabet = 'abcdefghijklmnopqrstuvwxyz'.split('') const numbers = '0123456789'.split('') const idLength = value || 6 let id = '' for(let i = 0; i < idLength; i++) { const numOrAlpha = ranNum(2) numOrAlpha === 1? id += alphabet[ranNum(alphabet.length - 1)]: id += numbers[ranNum(numbers.length - 1)] } return id } function isAllNumbers(arr) { return arr.every(value => Number.isInteger(+value)) } function allNumberId() { let count = 0 let ranNum = createRanId(2).split(""); while(.isAllNumbers(ranNum)) { ranNum = createRanId(2),split("") count++ } return [count. ranNum] } console.log(allNumberId())

Your check could also be done as

const isInvalid = yourString.split("").map(Number).some(isNaN)

Answer 2

The problem is the usage of Number.isInteger . You're actually passing strings there (single-character strings consisting of a digit or a alphabet char), which is never a number (integer or not) so Number.isInteger always returns false and your isAllNumbers function doesn't recognice what it should.