Files not being obfuscated

Previously I am facing this issue:
"TypeError: Cannot read property 'transformFile' of undefined"

But It is resolved by this code.
getTransformModulePath: () => {
return require.resolve('./transformer');
}

But after creating build, code is not being obfuscated.
And I want to obfuscate single file instead of "src" folder.

Please help.
Thanks.

Start by reproducing the build after setting getTransformModulePath to require.resolve('./transformer'), then inspect how the transformer is invoked for the generated build and for the src folder. Confirm what input is passed when obfuscating a single file and verify that the resulting build output is obfuscated.

Written by the indexing model from the issue text.