Summary

This pull request adds highlight_type support to files.completeUploadExternal and the filesUploadV2 method.

The highlight_type parameter allows specifying the file type hint for uploads (e.g. png, jpg, gif), enabling optimistic rendering before the async upload processing job completes.

📚 https://docs.slack.dev/reference/methods/files.completeUploadExternal/

Changes

• Added highlight_type to the FileUploadComplete interface (per-file in the files array)
• Added highlight_type to FileUploadV2 so it can be specified when using filesUploadV2
• Updated getAllFileUploadsToComplete to pass highlight_type through to each file object

Usage

import { LogLevel, WebClient } from '@slack/web-api';

const client = new WebClient(process.env.SLACK_BOT_TOKEN, { logLevel: LogLevel.DEBUG });

await client.filesUploadV2({
  channel_id: 'C0123456789',
  file: './image.png',
  filename: 'image.png',
  title: 'Image Upload',
  highlight_type: 'png',
  initial_comment: 'Uploaded with highlight_type for optimistic rendering',
});

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.