MobX 源码解析-observable

"scripts": {
    "quick-build": "tsc --pretty",
    "small-build": "node scripts/build.js"
},

![image](https://p3-juejin.byteimg.com/tos-cn-i-k3u1fbpfcp/501fc5efbdfc44769b2555bc25836f62~tplv-k3u1fbpfcp-zoom-1.image)

import { observable, action } from '../../mobx-source/mobx';

function createObservable(v, arg2, arg3) {
    debugger;
    ...
}

@inject('counterStore')
@observer
class Index extends Component {
    constructor(props) {
        super(props);
    }

    render() {
        const { counterStore } = this.props;
        return (
            <section>
                <button onClick={() => counterStore.add()}>+</button>
                <span>count is: {counterStore.obj.count}</span>
                <button onClick={() => counterStore.reduce()}>-</button>
            </section>
        );
    }
}

import { observable, action } from '../../mobx-source/mobx';
class CounterStore {
    @observable obj = {
        count: 0
    };

    @action
    add() {
        this.obj.count++;
    }

    @action
    reduce() {
        this.obj.count--;
    }
}

export default CounterStore;

export { observable, action, runInAction } from "./internal";

export * from "./api/action";
export * from "./api/autorun";
export * from "./api/observable";

function createObservable(v, arg2, arg3) {
    // @observable someProp;
    if (typeof arguments[1] === "string" || typeof arguments[1] === "symbol") {
        return deepDecorator.apply(null, arguments);
    }
    // it is an observable already, done
    if (isObservable(v))
        return v;
    // something that can be converted and mutated?
    const res = isPlainObject(v)
        ? observable.object(v, arg2, arg3)
        : Array.isArray(v)
            ? observable.array(v, arg2)
            : isES6Map(v)
                ? observable.map(v, arg2)
                : isES6Set(v)
                    ? observable.set(v, arg2)
                    : v;
}

const observableFactories = {
    box(value, options) {
        ...
    },
    array(initialValues, options) {
        ...
    },
    map(initialValues, options) {
        ...
    },
    set(initialValues, options) {
        ...
    },
    object(props, decorators, options) {
        ...
    },
    ref: refDecorator,
    shallow: shallowDecorator,
    deep: deepDecorator,
    struct: refStructDecorator
};

export function createDecoratorForEnhancer(enhancer) {
    invariant(enhancer);
    const decorator = createPropDecorator(true, (target, propertyName, descriptor, _decoratorTarget, decoratorArgs) => {
        if (process.env.NODE_ENV !== "production") {
            invariant(!descriptor || !descriptor.get, `@observable cannot be used on getter (property "${stringifyKey(propertyName)}"), use @computed instead.`);
        }
        const initialValue = descriptor
            ? descriptor.initializer
                ? descriptor.initializer.call(target)
                : descriptor.value
            : undefined;
        asObservableObject(target).addObservableProp(propertyName, initialValue, enhancer);
    });
    const res =
    // Extra process checks, as this happens during module initialization
    typeof process !== "undefined" && process.env && process.env.NODE_ENV !== "production"
        ? function observableDecorator() {
            // This wrapper function is just to detect illegal decorator invocations, deprecate in a next version
            // and simply return the created prop decorator
            if (arguments.length < 2)
                return fail("Incorrect decorator invocation. @observable decorator doesn't expect any arguments");
            return decorator.apply(null, arguments);
        }
        : decorator;
    res.enhancer = enhancer;
    return res;
}

export function createPropDecorator(propertyInitiallyEnumerable, propertyCreator) {
    return function decoratorFactory() {
        let decoratorArguments;
        const decorator = function decorate(target, prop, descriptor, applyImmediately
        // This is a special parameter to signal the direct application of a decorator, allow extendObservable to skip the entire type decoration part,
        // as the instance to apply the decorator to equals the target
        ) {
            ...
            if (!Object.prototype.hasOwnProperty.call(target, mobxPendingDecorators)) {
                const inheritedDecorators = target[mobxPendingDecorators];
                addHiddenProp(target, mobxPendingDecorators, Object.assign({}, inheritedDecorators));
            }
            target[mobxPendingDecorators][prop] = {
                prop,
                propertyCreator,
                descriptor,
                decoratorTarget: target,
                decoratorArguments
            };
            return createPropertyInitializerDescriptor(prop, propertyInitiallyEnumerable);
        };
    };
}

object(props, decorators, options) {
    if (typeof arguments[1] === "string")
        incorrectlyUsedAsDecorator("object");
    const o = asCreateObservableOptions(options);
    if (o.proxy === false) {
        return extendObservable({}, props, decorators, o);
    }
    else {
        const defaultDecorator = getDefaultDecoratorFromObjectOptions(o);
        const base = extendObservable({}, undefined, undefined, o);
        const proxy = createDynamicObservableObject(base);
        extendObservableObjectWithProperties(proxy, props, decorators, defaultDecorator);
        return proxy;
    }
},

export function createDynamicObservableObject(base) {
    const proxy = new Proxy(base, objectProxyTraps);
    base[$mobx].proxy = proxy;
    return proxy;
}

const objectProxyTraps = {
    has(target, name) {
        ...
    },
    get(target, name) {
        ...
    },
    set(target, name, value) {
        ...
    },
    deleteProperty(target, name) {
        ...
    },
    ownKeys(target) {
        ...
    },
    preventExtensions(target) {
        ...
    }
};