JS对象具有属性深层检查 [英] JS object has property deep check

问题描述

假设我们有JS对象：

var object = {
   innerObject:{
       deepObject:{
           value:'Here am I'
       }
   }
};

我们如何检查值属性是否存在？
我只能看到两种方式：

How can we check if value property exists? I can see only two ways:

第一个：

if(object && object.innerObject && object.innerObject.deepObject && object.innerObject.deepObject.value) {
    console.log('We found it!');
}

第二个：

if(object.hasOwnProperty('innerObject') && object.innerObject.hasOwnProperty('deepObject') && object.innerObject.deepObject.hasOwnProperty('value')) {
    console.log('We found it too!');
}

但有没有办法进行深入检查？让我们说，比如：

But is there a way to do a deep check? Let's say, something like:

object['innerObject.deepObject.value']

或

object.hasOwnProperty('innerObject.deepObject.value')

推荐答案

没有这种检查的内置方式，但您可以轻松实现它。创建一个函数，传递一个表示属性路径的字符串，通过。拆分路径并迭代这条路径：

There isn't a built-in way for this kind of check but you can implement it easily. Create a function, pass a string representing the property path, split the path by . and iterate over this path:

Object.prototype.hasOwnNestedProperty = function(propertyPath){
    if(!propertyPath)
        return false;

    var properties = propertyPath.split('.');
    var obj = this;

    for (var i = 0; i < properties.length; i++) {
        var prop = properties[i];

        if(!obj || !obj.hasOwnProperty(prop)){
            return false;
        } else {
            obj = obj[prop];
        }
    }

    return true;
};

// Usage: 
var obj = {
   innerObject:{
       deepObject:{
           value:'Here am I'
       }
   }
}

obj.hasOwnNestedProperty('innerObject.deepObject.value');

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