drawing-board/src/board/helper/stack-var.ts

import { Container } from "../packages";

type Var = { [key in string]: any };
type Key = Container;

const stackMap = new WeakMap<Key, Var[]>();
const getStack = (key: Key) => {
  const stack = stackMap.get(key);
  return stack || null;
};

const getCurrentVar = (key: Key) => {
  const stack = getStack(key);
  if (stack) {
    return stack[stack.length - 1];
  } else {
    throw "当前 key 不存在变量桟";
  }
};

export const varMount = (key: Key) => {
  const stack = getStack(key);
  if (!stack) {
    stackMap.set(key, []);
  } else {
    throw "当前 key 已挂载变量";
  }
};

export const varPush = (key: Key, data: Var) => {
  const stack = getStack(key);
  if (stack) {
    stack.push(data);
  }
};

export const varPop = (key: Key) => {
  const stack = getStack(key);
  if (stack?.length) {
    stack.pop();
  }
};

export const varAdd = (key: Key, k: string, v: any) => {
  const current = getCurrentVar(key);
  if (k in current) {
    throw `${key}变量已存在${current}`;
  } else {
    current[k] = v;
  }
};

export const varSet = (key: Key, k: string, v: any) => {
  const current = getCurrentVar(key);
  if (k in current) {
    throw `${key}变量已存在${current}`;
  } else {
    current[k] = v;
  }
};

export const varDel = (key: Key, k: string) => {
  const current = getCurrentVar(key);
  if (!(k in current)) {
    throw `${key}变量不存在${current}`;
  } else {
    delete current[k];
  }
};

const keyStack: Key[] = [];
export let currentVar: Var;
export const useVar = (key: Key) => {
  keyStack.push(key);
  currentVar = getCurrentVar(keyStack[keyStack.length - 1]);

  return () => {
    keyStack.pop();
    if (keyStack.length) {
      currentVar = getCurrentVar(keyStack[keyStack.length - 1]);
    } else {
      currentVar = null;
    }
  };
};