Handwritten number group chunk

(1) The realization result of chunk

(1) If size is greater than or equal to 1 and less than the length of the array

var arr = [1, 2, 3, 4, 5, 6, 7]
var res = arr.chunk(7)
console.log(res)

 

var arr = [1, 2, 3, 4, 5, 6, 7]
var res = arr.chunk(3)
console.log(res)

 

(2) Default 1 if no value is passed

var arr = [1, 2, 3, 4, 5, 6, 7]
var res = arr.chunk()
console.log(res)

 (3) The passed value is a negative number, the default is 1

var arr = [1, 2, 3, 4, 5, 6, 7]
var res = arr.chunk(-1)
console.log(res)

 

(2) Handwritten chunk

Array.prototype.chunk = function (size) {
      // 如果是空数组 直接返回就行了
      if (this.length === 0) {
        return this
      }
      // size 判断左右区间
      var size = size > 1 ? (size > this.length ? this.length: size) : 1
      // 结果
      let result = []
      // 小区块
      let smallChunk = []
      // this 指调用chunk方法的数组
      this.forEach((item) => {
        smallChunk.push(item)
        if (smallChunk.length === size) { // 每一个小碎片长度够了
          result.push(smallChunk)
          smallChunk = [] // 重置
        }
      })
      if (smallChunk.length > 0) {
        result.push(smallChunk) // 最后一次 长度不够size剩余的也加进去
      }
      return result
    }