stock-indicator/src/idicators/expma.ts

Stock Indicator Library

import {
  funEMA,
  funRound,
  TMixed,
  checkArrayOfNumbers,
  checkNumber,
} from "../common/index";

/**
 * - Exponential Moving Average (EMA)
 * @param {number[]} CLOSE - closing prices of the stock
 * @param {number} M1 - number of periods to calculate the EMA，must be greater than 1 and less than the length of the CLOSE array,default is 12
 * @param {number} M2 - number of periods to calculate the initial EMA, default is 1，must be less than N,default is 50
 * @returns {{ EMA: TMixed[] }} - object with the EMA values，rounded to 3 decimal places
 */
export function EXPMA(
  CLOSE: number[],
  M1: number = 12,
  M2: number = 50
): { EMA1: TMixed[]; EMA2: TMixed[] } {
  // - check input data
  checkArrayOfNumbers(CLOSE, "CLOSE");
  checkNumber(M1, 2, CLOSE, "M1", "CLOSE");
  checkNumber(M2, 2, CLOSE, "M2", "CLOSE");
  const EMA1 = funEMA(CLOSE, M1, 1).map((item) => funRound(item, 3));
  const EMA2 = funEMA(CLOSE, M2, 1).map((item) => funRound(item, 3));
  return { EMA1, EMA2 };
}