Ramda Classifier

Introduce Ramda a practical functional library for JavaScript/TypeScript by Naive Bayes classifier script.

It's code after refactoring from refactoring tutorial from a book Refactoring JavaScript: Turning Bad Code Into Good Code

This repo refactor the original code into a functional programming style version by adopting Ramda.

• original code

https://github.com/MingJen/ChordTrain/blob/main/TypeScript/main.ts

• code after refactoring

https://github.com/guAnsunyata/ramda-classifier-example/blob/main/src/script/classifier.ts

https://github.com/guAnsunyata/ramda-classifier-example/blob/main/src/script/records-of.ts

https://github.com/guAnsunyata/ramda-classifier-example/blob/main/src/main.ts

Read the Source Code

Naive Bayes classifier

see classifier

Query records in specific parameters for calculating classifier probability

see record-of see test case of record-of

Test final result for refactoring code from the book

see test final result

Introduce readibility

Make formula of Naive Bayes classifier more clear. Use query function in a declarative way to indicate the probability concepts. Rather than generating snapshot maps imperatively.

const categoryProbability = (category) =>
  length(recordOf(category)) / length(records) + smooth

const attrProbability = (category, attr) =>
  length(recordOf(category, attr)) / length(records)

Implementation of query function

export const recordsOf: RecordOf = (records) => (category, attr) =>
  filter(
    both(
      matchCategory(category),
      ifElse(always(!!attr), matchAttr(attr), always(true))
    ),
    records
  )

const matchCategory = (category) => pipe(prop('category'), equals(category))
const matchAttr = (attr) => pipe(prop('attrs'), find(equals(attr)))