$3

// or ES6
import Wordfreq from 'wordlevel'
var wordlevel = new wordlevel('en')

// constructor code will load the language list, lemmatize each word then index for quick lookups
// this adds a few ms to the object creation time but allows for easy language addition

// FREQUENCY: check the position of any word in a normalized dictionary
wordlevel.frequency("Gasoline")
// 14970

// LEVEL: check the percentage level of any word in a normalized dictionary
wordlevel.level("Gasoline")
// 15.4 // %

// BLOCK LEVEL: check the word frequency reading level of a block of text
// calculates all words and then returns the word level at the 98% range
wordlevel.block_level("The quick brown cow jumped over the large black dog")
// 32

// TOPWORDS: Get most difficult words, defaults to top 2%
wordlevel.topwords("The quick brown cow jumped over the large black dog", [2])
// [ {word:'quick', count:1, level:14.3}, ... ]

$3

// NORMALIZE WORD: lowercases word to base lemma for dictionary lookup
// note: this is half-algorithmic, not dictionary-based, so results are not always perfect
// if you have a POS ([noun,verb,adj,adv]), you can increase accuracy
wordlevel.normalize_word("policing")
// police
wordlevel.normalize_word("Running", "verb")
// run
wordlevel.normalize_word("Running", "noun")
// running

// PARSE WORDS: breaks up text into an array of objects
// Utilizes the "compromise" NLM module
wordlevel.parse_str("That was soon over.")
// [
// {word:"That", pos:"noun", lemma:"that"},
// {word:"was", pos:"verb", lemma:"was"},
// {word:"soon", pos:"adj", lemma:"soon"},
// {word:"over.", pos:"", lemma:"over"}
// ]