amazon-dynamodb - DAX put Item 失败并显示“无法将未定义或 null 转换为对象”

Question

我试图为现有的 Lambda 函数配置 DAX，该函数将数据读取和写入 DynamoDB。在引入 DAX 之前一切正常，之后，写入停止工作，写入的数据没有任何变化。

在调试时，我发现它们因以下异常而失败：

Write operation failed without negative acknowledgement 
Cannot convert undefined or null to object
at Function.keys (<anonymous>)
at Function._encodeAttributeValueInternal (/var/task/node_modules/amazon-dax-client/src/AttributeValueEncoder.js:173:23)
at Function.encodeAttributes (/var/task/node_modules/amazon-dax-client/src/AttributeValueEncoder.js:144:29)
at Function.encodeValuesWithNames (/var/task/node_modules/amazon-dax-client/src/Encoders.js:227:55)
at Encoders.encodeValues (/var/task/node_modules/amazon-dax-client/src/Encoders.js:67:23)
at Promise.resolve.then (/var/task/node_modules/amazon-dax-client/generated-src/Stubs.js:163:24)
at propagateAslWrapper (/var/task/node_modules/async-listener/index.js:504:23)
at /var/task/node_modules/async-listener/glue.js:188:31
at /var/task/node_modules/async-listener/index.js:541:70
at /var/task/node_modules/async-listener/glue.js:188:31

Answer 1

正在写入的数据有一些“可选”字段。正在编写的项目是这样的：

{
    requiredField1: "Some value",
    requiredField2: true,
    optionalField1: "abc",
    optionalField2: null,
    optionalField3: undefined,
}

DynamoDB 一切都很好，很漂亮，没有抱怨，但显然 DAX 对undefined. 改变它null让我克服了错误。