Vue2 响应式系统之深度响应

目录

• 1、场景
• 2、方案
• 3、场景2
• 4、总结

import { observe } from "./reactive";
import Watcher from "./watcher";
const data = {
    text: {
        innerText: {
            childText: "hello",
        },
    },
};
observe(data);
const updateComponent = () => {
    console.log(data.text.innerText.childText);
};

new Watcher(updateComponent);
data.text.innerText.childText = "liang";

import { observe } from "./reactive";
import Watcher from "./watcher";
const data = {
    text: {
        innerText: {
            childText: "hello",
        },
    },
};
observe(data);
const updateComponent = () => {
    console.log(data.text.innerText.childText);
};

new Watcher(updateComponent);
data.text = {
    innerText: {
        childText: "liang",
    },
};

/*******************新增 shallow*******************/
export function defineReactive(obj, key, val, shallow) {
/****************************************************/
    const property = Object.getOwnPropertyDescriptor(obj, key);
    // 读取用户可能自己定义了的 get、set
    const getter = property && property.get;
    const setter = property && property.set;
    // val 没有传进来话进行手动赋值
    if ((!getter || setter) && arguments.length === 2) {
        val = obj[key];
    }
    const dep = new Dep(); // 持有一个 Dep 对象，用来保存所有依赖于该变量的 Watcher
    /*******************新增****************************/
    !shallow && observe(val);
  	/******************************************************/
    Object.defineProperty(obj, key, {
        enumerable: true,
        configurable: true,
        get: function reactiveGetter() {
            const value = getter ? getter.call(obj) : val;
            if (Dep.target) {
                dep.depend();
            }
            return value;
        },
        set: function reactiveSetter(newVal) {
            const value = getter ? getter.call(obj) : val;

            if (setter) {
                setter.call(obj, newVal);
            } else {
                val = newVal;
            }
            dep.notify();
        },
    });
}

/*
util.js
export function isObject(obj) {
    return obj !== null && typeof obj === "object";
}
*/
export function observe(value) {
    if (!isObject(value)) {
        return;
    }
    let ob = new Observer(value);
    return ob;
}

import { observe } from "./reactive";
import Watcher from "./watcher";
const data = {
    text: {
        innerText: {
            childText: "hello",
        },
    },
};
observe(data);
const updateComponent = () => {
    console.log(data.text.innerText.childText);
};

new Watcher(updateComponent);

data.text.innerText.childText = "liang";
data.text = {
    innerText: {
        childText: "liang2",
    },
};

data.text.innerText.childText = "liang3";

data.text = {
    innerText: {
        childText: "liang2",
    },
};

/**
 * Define a reactive property on an Object.
 */
export function defineReactive(obj, key, val, shallow) {
    const property = Object.getOwnPropertyDescriptor(obj, key);
    // 读取用户可能自己定义了的 get、set
    const getter = property && property.get;
    const setter = property && property.set;
    // val 没有传进来话进行手动赋值
    if ((!getter || setter) && arguments.length === 2) {
        val = obj[key];
    }
    const dep = new Dep(); // 持有一个 Dep 对象，用来保存所有依赖于该变量的 Watcher

    let childOb = !shallow && observe(val);
    Object.defineProperty(obj, key, {
        enumerable: true,
        configurable: true,
        get: function reactiveGetter() {
            const value = getter ? getter.call(obj) : val;
            if (Dep.target) {
                dep.depend();
            }
            return value;
        },
        set: function reactiveSetter(newVal) {
            const value = getter ? getter.call(obj) : val;

            if (setter) {
                setter.call(obj, newVal);
            } else {
                val = newVal;
            }
          /******新增 *************************/
            childOb = !shallow && observe(newVal);
           /************************************/
            dep.notify();
        },
    });
}