Global

Methods

arrayCount(x) → {number}

arrayCount

Count the number of valid numeric values in the array.

Parameters:
Name Type Description
x Array.<*>

Input array.
Source:
Returns:
  • Count of numbers (excluding nulls and invalid values).
Type
number

arrayMax(x) → {number|null}

arrayMax

Return the largest number from the array, ignoring any non-numeric values. Returns null if no valid numbers are present.

Parameters:
Name Type Description
x Array.<*>

Input array.
Source:
Returns:
  • Maximum number or null if none found.
Type
number | null

arrayMean(x) → {number|null}

arrayMean

Calculate the average (mean) of valid numbers in the array. Returns null if no valid numbers are present.

Parameters:
Name Type Description
x Array.<*>

Input array.
Source:
Returns:
  • Mean of valid values or null.
Type
number | null

arrayMin(x) → {number|null}

arrayMin

Return the smallest number from the array, ignoring any non-numeric values. Returns null if no valid numbers are present.

Parameters:
Name Type Description
x Array.<*>

Input array.
Source:
Returns:
  • Minimum number or null if none found.
Type
number | null

arraySum(x) → {number|null}

arraySum

Sum all valid numeric values in the array. Returns null if all values are invalid.

Parameters:
Name Type Description
x Array.<*>

Input array.
Source:
Returns:
  • Sum of numbers or null if no valid values.
Type
number | null

dailyStats(datetime, x, timezone) → {object}

Calculate daily statistics over a time series of hourly values.

Returns five arrays of daily values:

  • datetime -- Luxon DateTime marking the start of each day (local time)
  • count -- Number of valid hourly values each day
  • min -- Minimum value each day
  • mean -- Mean value each day
  • max -- Maximum value each day
Parameters:
Name Type Description
datetime Array.<DateTime>

Hourly UTC timestamps as Luxon DateTime objects.
x Array.<number>

Array of hourly values.
timezone string

Olson time zone (e.g. "America/Los_Angeles").
Source:
Returns:
  • Object with datetime, count, min, mean, and max arrays.
Type
object

diurnalStats(datetime, x, timezone, dayCount) → {object}

Calculate hourly (diurnal) statistics over recent days.

Returns five arrays of hourly values:

  • hour -- Local-time hour of day [0–23]
  • count -- Number of non-missing values per hour
  • min -- Minimum value at each hour
  • mean -- Mean value at each hour
  • max -- Maximum value at each hour

By default, the most recent 7 full days are used.

Parameters:
Name Type Description
datetime Array.<DateTime>

Hourly UTC timestamps as Luxon DateTime objects.
x Array.<number>

Matching array of values (e.g. PM2.5).
timezone string

Olson timezone string (e.g. "America/Los_Angeles").
dayCount number

Number of days to include (default: 7).
Source:
Returns:
  • Object with hour, count, min, mean, and max arrays.
Type
object

pm_nowcast(pm) → {Array.<(number|null)>}

Calculate an array of NowCast values from hourly PM measurements.

Uses a 12-hour rolling window and the EPA NowCast algorithm to calculate weighted averages. Missing values should be represented by null.

The returned array is the same length as the input, but early entries may contain null due to insufficient data.

Parameters:
Name Type Description
pm Array.<(number|null)>

Hourly PM2.5 or PM10 values (no gaps).
Source:
Returns:
  • Array of NowCast values, rounded to 1 decimal place.
Type
Array.<(number|null)>

roundAndUseNull(x, digits) → {Array.<(number|null)>}

roundAndUseNull

Convert an array of numbers to an array where each number is rounded to a fixed number of decimal places. Any value that is not a valid number (NaN, undefined, null) will be converted to null.

Parameters:
Name Type Description
x Array.<number>

The input array of values.
digits number

Number of decimal places to round to (default is 1).
Source:
Returns:
  • New array with rounded values or nulls.
Type
Array.<(number|null)>

trimDate(datetime, x, timezone) → {object}

Trim a time series to full local calendar days.

Discards any partial days at the beginning or end of the array. Uses the local time zone to determine day boundaries, but always returns timestamps in UTC.

Parameters:
Name Type Description
datetime Array.<DateTime>

Array of Luxon DateTime objects (in UTC).
x Array.<number>

Array of measurements (same length as datetime).
timezone string

IANA/Olson timezone (e.g. "America/Los_Angeles").
Source:
Returns:
  • Object with datetime and x arrays trimmed to full days.
Type
object

useNull(x) → {Array.<(number|null)>}

useNull

Convert an array so that any undefined, null, or non-numeric (NaN) values are replaced by null.

Parameters:
Name Type Description
x Array.<*>

Input array with possibly invalid values.
Source:
Returns:
  • Cleaned array with only numbers or nulls.
Type
Array.<(number|null)>