javascript - 为什么这是无限循环？

Question

我试图将三个字符串放入一个大小为 9 的数组中，该数组将三个字符串放置在数组中的随机索引处，但我试图这样做会导致无限循环

const ticketArray = [];
const victoryMultipliers = ["x10", "x20", "x30", "x40", "x50", "x60"];

const threeOfThem = [];
let arr = []
let randStr = "";
for (let i = 0; i < 3; i++) {
    threeOfThem[i] = victoryMultipliers[Math.floor(Math.random() * victoryMultipliers.length)]
    randStr = threeOfThem[i]
    //console.log(randStr)

    arr = threeOfThem.filter(val => val === randStr)

    if (arr.length >= 2) {
        threeOfThem.pop();
        i--;
    }

}
const threeTicketArray = threeOfThem;
/// So above we have an array of example ["x20", "x50", "x30"]

// so below is where we have some problem

let randInt;
let tempStr = "";
for (let i = 0; i < 10; i++) { // i want to make an array.length of 9
    randInt = Math.floor( Math.random() * 3 );
    tempStr = threeTicketArray[randInt]; // to find the "x30" or whichever i stored

  ticketArray.push(tempStr); // push it into the ticketArray
  let len = ticketArray.filter(val => val === tempStr) // we filter to bring out the once for this loops iteration

    if ( len.length > 3 ) { // if I have 4 of example "x30"
        ticketArray.pop(); // I remove it as it was the last "x30" string added to the array
      i--; // I subtract the iteration by 1 so I can restart the this iteration of the loop
    }
}
// the end of the loop
console.log(ticketArray);

因此，我随机希望 ticketArray 的大小为 9，将票证字符串放置在随机索引处，并且每个字符串出现 3 次。但是，我遇到了无限循环，我不明白为什么!

Answer 1

请参阅下面的解决方案，并告诉我您的想法

const ticketArray = [];
const victoryMultipliers = ["x10", "x20", "x30", "x40", "x50", "x60"];

const threeOfThem = [];
let arr = []
let randStr = "";
for (let i = 0; i < 3; i++) {
    threeOfThem[i] = victoryMultipliers[Math.floor(Math.random() * victoryMultipliers.length)]
    randStr = threeOfThem[i]
    //console.log(randStr)

    arr = threeOfThem.filter(val => val === randStr)

    if (arr.length >= 2) {
        threeOfThem.pop();
        i--;
    }
    
}
const threeTicketArray = threeOfThem;
/// So above we have an array of example ["x20", "x50", "x30"]

// so below is where we have some problem


let randInt;
let tempStr = "";
for (let i = 0; i < 10; i++) { // i want to make an array.length of 9
    randInt = Math.floor( Math.random() * 3 );
    tempStr = threeTicketArray[randInt]; // to find the "x30" or whichever i stored

  ticketArray.push(tempStr); // push it into the ticketArray
  let len = ticketArray.filter(val => val === tempStr) // we filter to bring out the once for this loops iteration
  
    if ( len.length > 3 ) { // if I have 4 of example "x30"
        ticketArray.pop(); 
        // this should solve the infinit loop issue. 
        // as it seems that randInt is generating duplicated.
        if (ticketArray.length <9)
           i-- 
    }
}
// the end of the loop
console.log(ticketArray);