utilities.js

/** @format */

const debug = require('debug')('utilities')

function padToTwoCharacters(x, padWithChar = '0') {
  debug(`padToTwoCharacters(${x}, ${padWithChar}) called...`)
  if (x.toString().length < 2) {
    debug(`...returning ${padWithChar.concat(x)}`)
    return padWithChar.concat(x)
  } else {
    return x
  }
}

/*
 * Calculate moving average
 * Uses forEach loop
 * Slightly more performant for smaller periods
 */
function calcMovingAverage(arr, per, emptyVal = 0) {
  if (arr.length <= per) {
    console.error(
      `Array must be longer than the period ${per}. Supplied array is only ${arr.length} elements.`
    )
    return []
  }
  console.time('calcMovingAverage')
  let ndx = -1
  let resp = []
  arr.forEach((n) => {
    ndx++
    if (ndx >= per - 1) {
      resp.push(arr.slice(ndx - per + 1, ndx + 1).reduce((a, c) => a + c) / per)
    } else {
      resp.push(emptyVal)
    }
  })
  console.timeEnd('calcMovingAverage')
  return resp
}

function tagCache(c, ttl = 0) {
  if (c.cache && c.cache.status) {
    // Not stamped yet
    c.cache.status = 'used'
  }
  return c
}

const CACHE_TTL = 600

exports.CACHE_TTL = CACHE_TTL
exports.tagCache = tagCache
exports.padToTwoCharacters = padToTwoCharacters
exports.calcMovingAverage = calcMovingAverage