avsc.parse() lost some configuration of type about avsc

[mtth]

It depends.

If you'd simply like to keep the schema as-is (but not do anything with it), then you should use (for example) fs.readFileSync and JSON.parse and keep a reference to that schema:

var fs = require('fs');

var schema = JSON.parse(fs.readFileSync('./test.avsc')); // The complete schema.
var type = avsc.parse(schema); // If you'd also like the type.

(Types do not keep a reference to the schema that created them since that would either introduce consistency issues or require a deep-copy of arbitrary objects.)

If you'd like to introduce custom behavior from these non-standard fields (for example automatically transforming your long above into a JavaScript Date), you can use logical types. There is actually an example very similar to your use-case here.