Hi @Anonymous ,
How is the file created ? Will the text content ever have '{'. Its easy to get if No.
1. Manual trigger.
2. Get File Content
2. Split the File content based on '}' (Here I am assuming that your text will never have { as you re not giving more details
split(outputs('Get_file_content')?['body'],'{')
3. Now access the first element of the array and trim it using the trim function to remove the whitespaces.
trim(outputs('Compose')[0])
Hope this helps!