如何递归转换JS对象？解决数组被转为对象的问题

问题描述 #

需求是递归转换JavaScript对象：若对象仅包含label和value两个属性，则将其替换为label的值。但当前实现会把数组转换为对象，破坏原有结构。

输入对象 #

var input = {
        "general_detail_response": {
            "job_order_number": "J13197",
            "job_order_status": {
                "label": "Completed",
                "value": "COMPLETED"
            },
            "job_order_type": null,
        },
        "vehicle_details_response": [{
            "vehicle_number": "ssssadfwdf",
            "vehicle_type": {
                "label": "Standard Trailer",
                "value": "STANDARD_TRAILER"
            },
            "transporter_name": "sdfds",
            "shipping_details_responses": [{
                "shipping_bill_number": "qwer",
                "metrics_break_down": {
                    "nop": 1223,
                },
                "exporter_name": null
            }],
            "container_details_responses": null
        }],
        "ssr_response": [{
            "service_name": "22"
        }]
    };

原转换函数 #

function tranformFn(obj) {
    let output = {}
    for (var i in obj) {
        let o = obj[i];
        if (o instanceof Object) {
            if (o.label && o.value) output[i] = o.label;
            else output[i] = tranformFn(o);
        } else output[i] = o;
    }
    return output;
} 

当前错误输出 #

{
    "general_detail_response": {
        "job_order_number": "J13197",
        "job_order_status": "Completed",
        "job_order_type": null
    },
    "vehicle_details_response": {
        "0": {
            "vehicle_number": "ssssadfwdf",
            "vehicle_type": "Standard Trailer",
            "transporter_name": "sdfds",
            "shipping_details_responses": {
                "0": {
                    "shipping_bill_number": "qwer",
                    "metrics_break_down": {
                        "nop": 1223
                    },
                    "exporter_name": null
                }
            },
            "container_details_responses": null
        }
    },
    "ssr_response": {
        "0": {
            "service_name": "22"
        }
    }
}

期望输出 #

{
    "general_detail_response": {
        "job_order_number": "J13197",
        "job_order_status": "Completed",
        "job_order_type": null,
    },
    "vehicle_details_response": [{
        "vehicle_number": "ssssadfwdf",
        "vehicle_type": "Standard Trailer",
        "transporter_name": "sdfds",
        "shipping_details_responses": [{
            "shipping_bill_number": "qwer",
            "metrics_break_down": {
                "nop": 1223,
            },
            "exporter_name": null
        }],
        "container_details_responses": null
    }],
    "ssr_response": [{
        "service_name": "22"
    }]
};

问题原因 #

原函数存在两个核心问题：

1. 未区分数组与普通对象：无论输入是数组还是对象，都初始化output为{}，导致数组被强制转为对象。
2. 判断逻辑不严谨：仅检查o.label && o.value存在，未确保对象仅包含这两个属性，可能误替换其他包含label/value的复杂对象。

修正后的转换函数 #

function transformFn(obj) {
    // 根据输入类型初始化对应结构：数组用[]，对象用{}
    let output = Array.isArray(obj) ? [] : {};
    
    // 数组和对象分别处理循环逻辑
    if (Array.isArray(obj)) {
        obj.forEach((item, index) => {
            if (item && typeof item === 'object') {
                const keys = Object.keys(item);
                // 严格判断是否是仅含label和value的对象
                if (keys.length === 2 && keys.includes('label') && keys.includes('value')) {
                    output[index] = item.label;
                } else {
                    output[index] = transformFn(item);
                }
            } else {
                output[index] = item;
            }
        });
    } else {
        for (const key in obj) {
            if (obj.hasOwnProperty(key)) {
                const val = obj[key];
                if (val && typeof val === 'object') {
                    const keys = Object.keys(val);
                    if (keys.length === 2 && keys.includes('label') && keys.includes('value')) {
                        output[key] = val.label;
                    } else {
                        output[key] = transformFn(val);
                    }
                } else {
                    output[key] = val;
                }
            }
        }
    }
    return output;
}

验证结果 #

调用transformFn(input)后，输出与期望完全一致：数组结构被完整保留，仅含label和value的对象被替换为label的值，其他对象、null值均保持原有形态。

内容的提问来源于stack exchange，提问作者user5711656