AWS Lambda updating object in DynamoDB - amazon-web-services

Question

I'm trying to update object from DynamoDB for hours and I can't get it to work. I'm using DocumentClient library and its method update(). When I tested it with API Gateway, I got this error:
{
"errorType": "TypeError",
"errorMessage": "Cannot read property '_id' of undefined",
"trace": [
"TypeError: Cannot read property '_id' of undefined",
" at Runtime.exports.handler (/var/task/index.js:20:44)",
" at Runtime.handleOnce (/var/runtime/Runtime.js:66:25)"
]
}
Here is my code:
exports.handler = (event, context, callback) => {
console.log(event);
const id = event.listId;
const params = {
Key: {
"ListId": id
},
ExpressionAttributeNames: {
"#name": "Name",
"#shop": "Shop"
},
ExpressionAttributeValues: {
":name": event.listName,
":shop": {
"_id": event.listShop._id,
"name": event.listShop.name,
"address": event.listShop.address,
"city": event.listShop.city
}
},
TableName: "mk-lists",
UpdateExpression: "SET #name = :name, #shop = :shop"
};
dynamodb.update(params, (err, data) => {
if(err) {
console.log(err);
callback(err);
} else {
console.log(data);
callback(null, data);
}
});
};
I have Shop field in Lists table which is an object. Also, it is working when I test it in Lambda function. Can someone help me with this? Thanks in advance.
Here is my request body:
{
"listName": "Lista 13131",
"listShop": {
"_id": "933c836c-6868-4f56-a769-d59f5cbb231e",
"name": "DIS",
"address": "Podrinska 12",
"city": "Uzice"
}
}