如何检查 JSON 对象中的第一个值？

Question

我从 API 获取返回的 json 并且需要检查第一个对象 - 它没有键/值 - 用于 jQuery ajax 成功函数。通常，返回 JSON 格式

{"type":"Return","FirstName":"test","LastName":"test"}

我可以这样检查

success: function(data){
        if(data.type == "Return"){
            //do stuff  
        } else {
            //failed
        }
}

我如何执行相同类型的检查，以查看该对象的值是“税”还是“错误”？

{"tax":{"order_total_amount":1099.0,"shipping":0.0}}

success: function(data){
    if(data[0] == "tax"){
        //do stuff
    } else {
        //failed
    }
}

不起作用。我做错了什么？

这里是整个数据对象。 成功：

{"tax":{"order_total_amount":1099.0,"shipping":0.0,"taxable_amount":0.0,"amount_to_collect":0.0,"rate":0.0,"has_nexus":true,"freight_taxable":false,"tax_source":"destination","jurisdictions":{"country":"US","state":"CO","county":"ADAMS","city":"THORNTON"},"breakdown":{"taxable_amount":0.0,"tax_collectable":0.0,"combined_tax_rate":0.0,"state_taxable_amount":0.0,"state_tax_rate":0.0,"state_tax_collectable":0.0,"county_taxable_amount":0.0,"county_tax_rate":0.0,"county_tax_collectable":0.0,"city_taxable_amount":0.0,"city_tax_rate":0.0,"city_tax_collectable":0.0,"special_district_taxable_amount":0.0,"special_tax_rate":0.0,"special_district_tax_collectable":0.0,"line_items":[{"id":"1","taxable_amount":0.0,"tax_collectable":0.0,"combined_tax_rate":0.0,"state_taxable_amount":0.0,"state_sales_tax_rate":0.0,"state_amount":0.0,"county_taxable_amount":0.0,"county_tax_rate":0.0,"county_amount":0.0,"city_taxable_amount":0.0,"city_tax_rate":0.0,"city_amount":0.0,"special_district_taxable_amount":0.0,"special_tax_rate":0.0,"special_district_amount":0.0}]}}}

错误：

{"error":"Bad Request","detail":"to_zip 55478 is not used within to_state AL","status":400}

Answer 1

您可以使用Object.prototype.hasOwnProperty()。例如：

success: function(data) {
    if(data.hasOwnProperty("tax")) {
        //do stuff
    } else {
        //failed
    }
}