index.js

const natural = require('natural');
const isEmpty = require('lodash.isempty');
const normalize = require('./src/stages/normalize');
const tokenize = require('./src/stages/tokenize');
const stem = require('./src/stages/stem');
const removeEmptyToken = require('./src/stages/removeEmptyToken');
const removeDuplication = require('./src/stages/removeDuplication');
const tokens = require('./src/allowlist/tokens');

function isInvalidInput(input) {
  return (!input
    || typeof input !== 'object'
    || input.length <= 0)
    && typeof input !== 'string';
}

module.exports = (input) => {
  if (isInvalidInput(input)) {
    throw Error('Invalid Input!');
  }

  const listofingredients = typeof input === 'string' ? [input] : input;

  const nomalizedList = normalize(listofingredients);
  const tokenList = tokenize(nomalizedList);
  const tokenObjectList = stem.getListOfObjects(tokenList);

  const notBlankTokenObjects = removeEmptyToken(tokenObjectList);
  let resultList = notBlankTokenObjects.map((tokenObject) => tokenObject.word);

  const nounInflector = new natural.NounInflector();

  resultList = resultList.map((token) => nounInflector.singularize(token));
  const tokensSingularized = tokens.map((token) => nounInflector.singularize(token));

  resultList = resultList.map((token) => {
    if (tokensSingularized.includes(token)) {
      return token;
    }
    return '';
  });

  resultList = resultList.filter((token) => !isEmpty(token));

  return removeDuplication(resultList);
};