构建一个序列号数组

Question

我有一个传入数组：

[{step: 0, count: 1}, {step: 1, count: 5}, {step: 5, count: 5}]

所以我需要将传入的数组转换为另一个数组

[0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30]

我试过这样走：

const convertRangeData = (rangeData) =>
  {
  const convertedRangeData =
    rangeData.reduce( (acc, item) => 
        {
        const { step, count } = item;
        const prev                 = acc[acc.length - 1];
        return [...acc, ...[...Array(count)].fill(step).map((i, idx) => i * (idx + 1) + prev)];
        },[0] )
    return convertedRangeData;
  }

但我有

[0, 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30]

Answer 1

使用 Array.from() 创建一个包含范围内值的数组。然后迭代范围数组。

要创建连续范围，请减少 ranges 的数组。创建范围时，从累加器 (acc) 中取出最后一个数字，并将其用作起始值。

const range = ({ step, count }, start = 0) => 
  Array.from({ length: count }, (_, i) => (i + 1) * step + start)
  
const continuousRange = arr =>
  arr.reduce((acc, r) => acc.concat(range(r, acc[acc.length -1])), [])

const ranges = [{step: 0, count: 1}, {step: 1, count: 5}, {step: 5, count: 5}]

const result = continuousRange(ranges)

console.log(result)

Answer 2

我的方式

const ranges = [{step: 0, count: 1}, {step: 1, count: 5}, {step: 5, count: 5}] 

const convertRangeData = rangeData => rangeData.reduce((acc, {step,count}) =>
  {
  let prev = acc[acc.length - 1] || 0
  while(count--)
    acc.push(prev+=step)  
  return acc
  },[])

console.log( convertRangeData(ranges) )

构建一个序列号数组

Building an array of sequential numbers

javascript

arrays

reduce