Slack Node file upload error ? - options.channelIds.join is not a function

[0101binary0101]

Describe the problem/error/question

I’ve had a workflow working for 6+ months just uploading a graphic status to a slack channel but for the past two days the Slack File Upload node has stopped working. Send Slack messages is working without issues, it’s just the Slack File Upload has stopped working.

I’ve checked that the curl command of the API works ok - so it appears to be N8N file upload related ?

curl -F [email protected] -F "initial_comment=Test Curl File Upload" -F channels="#ignore-jka-channel" -H "Authorization: Bearer xoxb-SLACK-BOT-CRED" https://slack.com/api/files.upload

What is the error message (if any)?

Slack node - returns: options.channelIds.join is not a function

Please share your workflow

This workflow was from the 1.2.1 (next) docker instance, but the same happens on 1.1.1.

Share the output returned by the last node

Information on your n8n setup

• n8n version: Tried this on 1.1.1 and Postgres 1.2.1
• Database (default: SQLite): SQLite 1.1.1 , Postgres 1.2.1
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app): Docker self hosted
• Operating system: Redhat

[0101binary0101]

I figured it out !! It’s because of the old/new n8n usage syntax - caught me out

Slack Uploads wants it as an array of channels

I changed the slack node to turn it into an array in the expression.

{{ [$('Set').item.json["slackChannel"]] }}

This is it working now