JavaScript数组扁平化处理

1.ES6的flat

const arr = [1, [2, 3, [4, 5]]]
arr.flat(Infinity) 

2.递归

const arr = [1, [2, 3, [4, 5]]]

const flat = (arr) => {
	let result = []
  for (let i = 0, len = arr.length; i < len; i++ ) {
    Array.isArray(arr[i]) ? result = [...result, ...flat(arr[i])] : result.push(arr[i])
  }
  return result
}

flat(arr)

3.reduce + 递归

const arr = [1, [2, 3, [4, 5]]]

const flat = (arr) => {
  if (!Array.isArray(arr)) return
  return arr.reduce((prev, curr) => prev.concat(Array.isArray(curr) ? flat(curr) : curr), [])
}

flat(arr)

4.扩展运算符 + 迭代

const arr = [1, [2, 3, [4, 5]]]

const flat = (arr) => {
  while(arr.some((item) => Array.isArray(item))) {
  	arr = [].concat(...arr)
  }
  return arr
}

flat(arr)

5.序列化 + 正则

const arr = [1, [2, 3, [4, 5]]]

const flat = (arr) => {
  return JSON.parse(`[${JSON.stringify(arr).replace(/(\[|\])/g, '')}]`)
}

flat(arr)