Construct 2 only minifies c2runtime.js, not any other script files, so the sfs2x_api_js.js file in your picture will not have been touched by Construct 2.
If code in c2runtime.js refers to the external script, those terms will also be minified unless you write code which is compatible with Closure Compiler's advanced mode. This is all documented.
That means I'll never can use Smartfox API, when I minify my construct project?
Is there no way to say in script, dont minify this part?