Answer 1

力扣 25. K 个一组翻转链表

var reverseKGroup = function(head, k) {
    if (!head) return head
    let fast = head
    let i = k
    // 一. 判断是否够长
    while (i--) {
      if (fast) {
        fast = fast.next
      } else {
        return head
      }
    }
    // 二. 够长就翻转当前的k段
    let j = k
    let node = head
    let rev = null
    while (j--) {
      let temp = node.next
      node.next = rev
      rev = node
      node = temp
    }
    // 三. 递归
    head.next = reverseKGroup(node, k)
    return rev
};

不递归的写法

var reverseKGroup = function(head, k) {
    let reverseList = []
    let current = null
    let end = null
    let result = null
    while(head){
        if(reverseList.length < k){
            reverseList.push(head.val)
        }
        if(reverseList.length == k){
            while(reverseList.length>0){
                current = new ListNode(reverseList.pop())
                if(!end){
                    end = current
                }else{
                    end.next = current
                    end = current
                }
                if(!result){
                    result = current
                }

            }
        }
        head = head.next
    }
    while(reverseList.length>0){
        current = new ListNode(reverseList.shift())
        if(!end){
            end = current
        }else{
            end.next = current
            end = current
        }
        if(!result){
            result = current
        }

    }
    return result
};

Answer 2

p.line {
    overflow: hidden;
    -ms-text-overflow: ellipsis;
    text-overflow: ellipsis;
    display:-webkit-box; //将对象作为弹性伸缩盒子模型显示。
    -webkit-box-orient:vertical; //从上到下垂直排列子元素（设置伸缩盒子的子元素排列方式）
    -webkit-line-clamp: 2; // 显示行数，超出两行隐藏且多余的用省略号表示...
    line-clamp: 2;
    max-width: 210px; // 有必要定义max-width
}

Answer 3

这个primitify代码看的似懂非懂的，想尝试一下怎么用，但是不会用，能否有个例子让观摩学习一下

这样会好理解一点

function promisify (original) {
  return function () {
    return new Promise((resolve, reject) => {
      original(...arguments, (err, ...values) => {
        if (err) return reject(err);
        return resolve(...values);
      });
    });
  };
} 

Answer 4

@cendylee 就我看到的资料来说，好像是在task之间进行的。如果有更详细可靠的资料进行补充或更正当然更好。

Answer 5

Promise.prototype.myFinally = async function (cb) {
  const pr = this;
  try {
    await pr;
  } finally {
    cb && cb();
  }
};

const start = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      const temp = Math.round(Math.random());
      if (temp > 0.5) {
        resolve(temp);
      } else {
        reject(temp);
      }
    }, 2000);
  });
};

start()
  .then((res) => {
    console.log("res", res);
  })
  .catch((err) => {
    console.log("err", err);
  })
  .myFinally(() => {
    console.log("finally");
  });

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