Adding new (SPFX based) ecb Menu Item with showProperties function

powerCorner You can achieve similar functionality using JSON formatting with less efforts. Follow below steps:

1. Create a new single line of text column in document library

2. Format the newly created column using below JSON:

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "button",
  "txtContent": "Open properties",
  "customRowAction": {
    "action": "editProps"
  }
}

3. Hide this column from library forms (make it Hidden from advanced content type management settings).

Output:

On click of this button, file properties pane will be open at the right side. Optionally, you can apply styling to the button as per your requirements. for that check official documentation of JSON formatting.

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