HA.Close = (Open(0) + High(0) + Low(0) + Close(0)) / 4;
HA.Open = (HA.Open(-1) + HA.Close(-1)) / 2;
HA.High = MAX(High(0), HA.Open(0), HA.Close(0));
HA.Low = Min(Low(0), HA.Open(0), HA.Close(0));

// Where (0) means current candle, and (-1) means the previous candle

let result = [{
  open: 100,
  high: 200,
  low: 10,
  close: 50,
}, ...
]

var HeikinAshi = require("heikinashi");

let result = HeikinAshi([
  {
    time: 1525651200,
    close: 9377.81,
    high: 9662.23,
    low: 9202.13,
    open: 9643.99,
    volume: 73842.44,
  },
  ...
],
options{
  overWrite: false,  //overwrites the original data or create a new array
  formatNumbers: false, //formats the numbers and reduces their significant digits based on the values
  decimals: 4,  //number of significant digits
  forceExactDecimals: false //force the number of significant digits or reduce them if the number is high
});

console.log("result: ", JSON.stringify(result, null, 2));