# "TypeError: Cannot read property 'decoded\_payload' of undefined"
**URL:** https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087
**Category:** General
**Tags:** function-node
**Created:** [28 February 2022 03:21 UTC](https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087 "2022-02-28T03:21:10Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@rfrancis97](https://discourse.nodered.org/u/rfrancis97)
#### Post date: [28 February 2022 03:21 UTC](https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087/1 "2022-02-28T03:21:10Z")
When I inject code:
```auto
{
"received_at": "2022-02-27T23:45:18.013631675Z",
"uplink_message": {
"session_key_id": "AX88sOZsNTkoN5rZ+Rzx/Q==",
"f_port": 1,
"f_cnt": 80,
"frm_payload": "SGVsbG8sIHdvcmxkIQ==",
"decoded_payload": {
"degreesC": 20.20263671875,
"humidity": 38.1103515625
}
}
}
```
into function node:
```auto
var thing = [{
degreesC: msg.payload.uplink_message.decoded_payload.degreesC,
humidity: msg.payload.uplink_message.decoded_payload.humidity,
}]
msg.payload = thing;
return msg;
```
I get
```auto
2/27/2022, 7:06:04 PMnode: a99be1c0d3d3695d
msg.payload : array[1]
array[1]
0: object
degreesC: 20.20263671875
humidity: 38.1103515625
```
So everything works fine. But when I feed the following (basically the same) MQTT payload into the same function:
```auto
{
"end_device_ids": {
"device_id": "eui-70b3d57ed004d388",
"application_ids": {
"application_id": "mqtt-rpi3b"
},
"dev_eui": "70B3D57ED004D388",
"join_eui": "0000000000000000",
"dev_addr": "260C0875"
},
"correlation_ids": [
"as:up:01FWYS5ZNTV0C25QZG3CZYW2WY",
"gs:conn:01FWY7ADE93XZZ8A72N1EHDH2S",
"gs:up:host:01FWY7ADJXWZWYHXHR5852CGS8",
"gs:uplink:01FWYS5ZF1JRJDHCP9SDDMN718",
"ns:uplink:01FWYS5ZF4TDHF5473B8CBK29V",
"rpc:/ttn.lorawan.v3.GsNs/HandleUplink:01FWYS5ZF4744HNW8ZJ25RDB26",
"rpc:/ttn.lorawan.v3.NsAs/HandleUplink:01FWYS5ZNS2ZXRQ5WT1B7GV9VX"
],
"received_at": "2022-02-27T23:45:18.013631675Z",
"uplink_message": {
"session_key_id": "AX88sOZsNTkoN5rZ+Rzx/Q==",
"f_port": 1,
"f_cnt": 80,
"frm_payload": "SGVsbG8sIHdvcmxkIQ==",
"decoded_payload": {
"degreesC": 20.20263671875,
"humidity": 38.1103515625
}
}
}
```
I get:
```auto
2/27/2022, 7:05:34 PMnode: Test
function : (error)
"TypeError: Cannot read property 'decoded_payload' of undefined"
```
I'm just learning this stuff, so be kind.
---
### Author:  [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)
#### Post date: [28 February 2022 07:29 UTC](https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087/2 "2022-02-28T07:29:26Z")
From what you have shown us, it seems your code and data are fine but obviously something else is going on. Lets add some debug messages to your function...
```auto
if(!msg.payload.uplink_message) {
node.warn(["this msg does not have '.payload.uplink_message' - look closely at its content", msg]);
}
var thing = [{
degreesC: msg.payload.uplink_message.decoded_payload.degreesC,
humidity: msg.payload.uplink_message.decoded_payload.humidity,
}]
msg.payload = thing;
return msg;
```
---
### Author:  [@rfrancis97](https://discourse.nodered.org/u/rfrancis97)
#### Post date: [28 February 2022 17:13 UTC](https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087/3 "2022-02-28T17:13:32Z")
I needed to "Always convert to JavaScript Object' by adding a JSON node before the function.
Thanks!
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [14 March 2022 17:13 UTC](https://discourse.nodered.org/t/typeerror-cannot-read-property-decoded-payload-of-undefined/59087/4 "2022-03-14T17:13:39Z")
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