javascript - 在嵌套的 json 对象中查找和更新

Question

我使用此代码从 sJhonny's Question 的 json 对象中找到所需的部分

数据样本

TestObj = {
    "Categories": [{
        "Products": [{
            "id": "a01",
            "name": "Pine",
            "description": "Short description of pine."
        },
        {
            "id": "a02",
            "name": "Birch",
            "description": "Short description of birch."
        },
        {
            "id": "a03",
            "name": "Poplar",
            "description": "Short description of poplar."
        }],
        "id": "A",
        "title": "Cheap",
        "description": "Short description of category A."
    },
    {
        "Product": [{
            "id": "b01",
            "name": "Maple",
            "description": "Short description of maple."
        },
        {
            "id": "b02",
            "name": "Oak",
            "description": "Short description of oak."
        },
        {
            "id": "b03",
            "name": "Bamboo",
            "description": "Short description of bamboo."
        }],
        "id": "B",
        "title": "Moderate",
        "description": "Short description of category B."
    }]
};

查找函数

function getObjects(obj, key, val) {
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));
        } else if (i == key && obj[key] == val) {
            objects.push(obj);
        }
    }
    return objects;
}

像这样使用:

getObjects(TestObj, 'id', 'A'); // Returns an array of matching objects

这段代码是从源中选择匹配的片段。但我想要的是用新值更新源对象并检索更新后的源对象。

我想要类似的东西

getObjects(TestObj, 'id', 'A', 'B'); // Returns source with updated value. (ie id:'A' updated to id:'B' in the returned object)

我的代码

function getObjects(obj, key, val, newVal) {
    var newValue = newVal;
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));
        } else if (i == key && obj[key] == val) {
            obj[key] = 'qwe';
        }
    }
    return obj;
}

如果我给 obj[key] = 'qwe';，这会起作用，但如果我将代码更改为 obj[key] = newValue;，它会更新为未定义。

为什么会这样？

Answer 1

你忘记在嵌套调用中传递 newValue

function getObjects(obj, key, val, newVal) {
    var newValue = newVal;
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val, newValue));
        } else if (i == key && obj[key] == val) {
            obj[key] = 'qwe';
        }
    }
    return obj;
}