[js函数] shallowEqual

const isBasicType = (t: any) => {
    return t === "number" || t === "string" || t === "boolean" || t === 'undefined';
}

/**
 * 数组和对象都能比较
 * @param a
 * @param b
 * @returns {boolean}
 */
function compareByObject(a:any,b:any){
    const keysA = Object.keys(a);
    const keysB = Object.keys(b);
    if (keysA.length !== keysB.length) {
        return false;
    }

    const bHasOwnProperty = Object.prototype.hasOwnProperty.bind(b);
    for (let idx = 0; idx < keysA.length; idx++) {
        const key = keysA[idx];
        if (!bHasOwnProperty(key) || a[key] !== b[key]) {
            return false;
        }
    }
    return true;
}

const shallowEqual = (a:any, b:any) => {

    const aType = typeof a;
    const bType = typeof b;

    if (aType !== bType) {
        return false;
    }

    if (isBasicType(aType) && isBasicType(bType)) {
        return a === b;
    }

    if (typeof a !== "object" || !a || typeof b !== "object" || !b) {
        return false;
    }

    if (a === b) {
        return true;
    }

    return compareByObject(a,b);
};

export {
    shallowEqual
}