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Ancillaries

accumulatedAverage

Utility for recalculating an average as the sample size increased. There are two ways of using the function, one-off and incremental, but both employ partial application.

One-off, involves calling acculmulateAverage with the current average and the size of the sample (number of values from which the average is calculated.) This provides the partial application (specialised function) that can then be called with the value to be included in the average.

Utility.accumulatedAverage(currentAverage, sampleSize)(newValue)

The incremental appraoch of using the function involves placing the initial call without parameters (or with the defaults), to get the specialised function.

const accumulateAverage = Utility.accumulatedAverage();

const newAverage = accumulateAverage(newSample)); // newAverage = (0 + newSample) / (0 + 1)

Subsequent calls to accumulateAverage with include additional values as part of the new average.

Parameters

This function employs 2-stage execution through currying.

Initial call

  • averageToDate: Current average before the new Value arrived. (defaulted to 0)
  • sampleSize: Number of values in the sample, including the new Value. (defaulted to 0)

Subsequent calls

  • newValue - New data point to be included in the average calculation.
  • newAverge - Replacement value of the averageToDate. (optional)
  • newSampleSize - Replacement value of the sampleSize. (optional)

Return Value

The new calculated average.

dateBasedRandom

Generates a random number based on the current Date-Time in milliseconds.

Parameters

None.

Return Value

A floating-point number greater than or equal to 0 and less than 1.

mapGetter

Utility for creating and retrieving entities from a map object.

Parameters

This function employs 2-stage execution through currying.

Initial call

  • mapInstance: The map instance potentially containing an entity.
  • entityFactory: Function for creating a new entity when not found in the map.

Subsequent calls

  • entityId - The Id of the entity to be retrieved from the map or created.
  • entityParams - An object containing additional paraeters required to create an entity. (optional)

Return Value

The entity retrieved from the map or created anew.

postJson

Generates the optons argument for a POST fetch request.

Parameters

  • data - the data to be send as the body of the fetch request (not stringified).
  • headers - optional object containing header properties.

Return Value

An object to be used for the POST fetch request containg all the (JSON) encoding and header values required.

random

Generates a number within the given range and to the stipulated precision.

Parameters

  • max - Highest value of the random range
  • min - Lowest value of the random range (default 0)
  • precision - Number of decimal digits allowed in the random value as a power of 10 (default 0 = 10^0)

Return Value

A function that generates a random value within the min and max range with a given decimal precision.

sum

Calculates the sum of all arguments supplied.

Parameters

  • ...nums - a (rest) array of numbers.

Return Value

The sum of all the provided values.

Exceptions

Code Description
E-NN Non-numeric value supplied.

webStore

Provides an object of web storage utility methods.

Parameters

  • keyName - storage key
  • localWebStorage - flag indicating the type of web storage (default true = localStorage, false = sessionStorage)

Return Value

An object of functions for the manipulation of data in Web Storage.

  • clear: Wipes all keys and values from web storage.
  • get: Retrieves the value from web storage with the previously given key.
  • remove: Wipes the specified key and value from the web storage.
  • set: Stores the value in web storage with the previously given key.