it has issue with serializer

it says this when i type in "node ." into terminal

TypeError: data.map is not a function
at encodeData (/Volumes/TOSHIBA EXT/emotion Detection in text/serializer.js:30:17)
at Object.serialize (/Volumes/TOSHIBA EXT/emotion Detection in text/serializer.js:39:40)
at Object. (/Volumes/TOSHIBA EXT/emotion Detection in text/app.js:6:22)
at Module._compile (internal/modules/cjs/loader.js:1085:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)
at Module.load (internal/modules/cjs/loader.js:950:32)
at Function.Module._load (internal/modules/cjs/loader.js:791:14)
at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
at internal/main/run_main_module.js:17:47

Start by running `node .` to reproduce the error, then inspect `serializer.js` around line 30 and `app.js` around line 6, where the stack trace points. Determine why the serializer receives a value without the expected `map` behavior; done means the command runs without this TypeError and serialization still works.

Written by the indexing model from the issue text.