@jianghh/canvas-graffiti/es/stack/index.js

canvas涂鸦库，支持手写、笔写、鼠标，选中元素，并且移动、删除等功能。集成撤销重做操作。

var r = Object.defineProperty;
var h = (t, e, i) => e in t ? r(t, e, { enumerable: !0, configurable: !0, writable: !0, value: i }) : t[e] = i;
var s = (t, e, i) => (h(t, typeof e != "symbol" ? e + "" : e, i), i);
class p {
  constructor(e) {
    s(this, "revokeList", []);
    s(this, "redoList", []);
    s(this, "preItem", null);
    // 存储上一步内容，由于撤销操作是需要滞后一步的，所以有个预备入栈的项
    s(this, "maxSize", 5);
    this.revokeList = [], e && (this.maxSize = e);
  }
  get revokeSize() {
    return this.revokeList.length;
  }
  get redoSize() {
    return this.redoList.length;
  }
  push(e) {
    this.revokeSize === this.maxSize ? this.revokeList.shift() : this.revokeSize > this.maxSize && (this.revokeList = this.revokeList.reverse().splice(0, this.maxSize - 1).reverse()), this.preItem && this.revokeList.push(this.preItem), this.preItem = e, this.redoList = [];
  }
  pop() {
    this.redoList.push(this.preItem);
    const e = this.revokeSize ? this.revokeList.pop() : null;
    return this.preItem = e, e;
  }
  popRedo() {
    if (this.redoSize) {
      const e = this.redoList.pop();
      return this.revokeList.push(this.preItem), this.preItem = e, e;
    } else
      return null;
  }
  clear() {
    this.revokeList = [], this.redoList = [], this.preItem = null;
  }
}
export {
  p as CacheStack
};