如何在JSONata中原地迭代修改对象内嵌套数组的amount属性

问题背景 #

我有一个JSON对象，其中policyList是数组类型，它的每个元素下包含product数组。我需要修改product数组中每个对象的amount值，但当前编写的表达式只能输出修改后的amount数组，无法保留完整的原对象结构。

原始JSON数据 #

{"admissionDate": "2023-10-04","claimCaseId": 123,"claimCaseStatusDescp": "Waiting","claimTypeDescp": "Hospitalization","dischargeDate": "2023-10-20","hospital": "abc","policyList": [{"policyNo": "P1","product": [{"amount": 10243,"claimDecision": "7","claimDecisionDescp": "Pending","productName": "Auto"},{"amount": 1023,"claimDecision": "7","claimDecisionDescp": "Pending","productName": "Mob"},{"amount": 100000,"claimDecision": "8","claimDecisionDescp": "Approved","productName": "PA"}]}],"reasonCode": ""}

错误表达式及当前输出 #

我之前写的表达式：

$map($.policyList.product.amount, function($amount) {
    $formatNumber($amount,'#,###')
})

当前输出（仅得到格式化后的amount数组）：

["10,243","1,023","100,000"]

期望输出 #

需要保留完整原对象结构，仅更新product中的amount值：

{"admissionDate": "2023-10-04","claimCaseId": 123,"claimCaseStatusDescp": "Waiting","claimTypeDescp": "Hospitalization","dischargeDate": "2023-10-20","hospital": "abc","policyList": [{"policyNo": "P1","product": [{"amount": "10,243","claimDecision": "7","claimDecisionDescp": "Pending","productName": "Auto"},{"amount": "1,023","claimDecision": "7","claimDecisionDescp": "Pending","productName": "Mob"},{"amount": "100,000","claimDecision": "8","claimDecisionDescp": "Approved","productName": "PA"}]}],"reasonCode": ""}

解决方案 #

使用JSONata的变换操作符（~>）结合数组遍历，实现只修改目标字段、保留其余结构的效果：

正确的JSONata表达式 #

$ ~> |policyList|{
  "product": $map(product, function($item) {
    $item ~> |{"amount": $formatNumber($item.amount, "#,###")}|
  })
}|

表达式说明 #

1. $ ~> |policyList|{...}|：对根对象的policyList数组进行变换，遍历数组中的每个元素。
2. 对每个policyList元素，重新定义product字段：用$map遍历原product数组。
3. $item ~> |{"amount": ...}|：对每个product对象，仅更新amount字段（用$formatNumber格式化），其余字段自动保留原始值。

这样就能在修改amount的同时，完整保留整个JSON对象的结构。

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