amlich.js
A Vietnamese lunar calendar calculator library written in JavaScript.
Another version which is written in Haskell https://github.com/codeaholicguy/halunar.
Usage
computeDateToLunarDate(dd, mm, yy, timeZone)
computeDateFromLunarDate(lunarDay, lunarMonth, lunarYear, lunarLeap, timeZone)
Example:
const {computeDateToLunarDate} = require('amlich.js')
console.log(computeDateToLunarDate(18, 7, 2018, 7))
// { lunarDay: 6, lunarMonth: 6, lunarYear: 2018, lunarLeap: false }