JS - 没有for或while循环重复动作N次？

Question

For example, I want to create some debug data array and I need a function that will take only the length of desired array and return array of objects with few props with random data values.

Is there a way to make this function without a for loop? The reason for the question is that I have this i variable that I don't really need.

const generateData = (count) => {
  let data = []
  for (let i = 0; i < count; i++)  
    data.push({
      foo: Math.round(Math.random() * 100),
      bar: Math.random() > 0.5
    })
  return data  

}

Answer 1

You can create the array all at once with Array.from , if you want, no declaration or usage of any intermediate variable names:

 const generateData = length => ( Array.from( { length }, () => ({ foo: Math.round(Math.random() * 100), bar: Math.random() > 0.5 }) ) ); console.log(generateData(5)); 

Answer 2

Instead of pushing every iteration into a target array you can create at once the array of size you need and then map each item to a random initiated value the way you need.

  function initArray(amount) { return [...new Array(amount)].map(() => ({ foo: Math.round(Math.random() * 100), bar: Math.random() > 0.5 })); } console.log(initArray(5)); 

Actually this is still an iterating but with more functional approach.

Answer 3

You can generate an array of n length and map() it to random objects.

 const createRandomArray = n => arr = [...Array(n)].map(() => ({ foo: Math.round(Math.random() * 100), bar: Math.random() > 0.5 })); console.log(createRandomArray(3)); 

Answer 4

You could make a recursive function:

const generateData = (count) => {
  let data = []
  function recursive(num) {
    if (num > 1) {
      num--;
      data.push({
        foo: Math.round(Math.random() * 100),
        bar: Math.random() > 0.5
      })
      recursive(num);
    }
    else {
      data.push({
        foo: Math.round(Math.random() * 100),
        bar: Math.random() > 0.5
      })
      return;
    }
  }
  recursive(count);
  return data  

}

Relatively large, but extremely simple to see what everything's doing.

Answer 5

 var timer = null; const generateData = (count,cb) => { let data = []; var num = 0; timer = setInterval(function(){ if(num>=count){ clearInterval(timer); cb(data) }else{ data.push({ foo: Math.round(Math.random() * 100), bar: Math.random() > 0.5 }) num++; } },10) } generateData(5,function(data){ console.log(data) })