BMI Percentile Calculator

This project defines a Javascript module BmiPercentileCalculator in UMD format.

BmiPercentileCalculator contains functions to calculate the english or metric body-mass index. These functions require a height, weight, and age in months.

BmiPercentileCalculator also contains a convenience function to compute a number of months between two dates. This is needed for the age input for the above functions.

The original source inspiration for the BMI calculation functions english() and metric() is:

• https://www.cdc.gov/healthyweight/bmi/bmi_calc.js

Building

This project uses webpack to create a UMD Javascript file suitable for use via a <script> tag or as a module suitable for inclusion via import or require.

npm install
npm run build

Testing via the Browser

This project includes a simple example index.html which includes the built module via a <script> tag and performs some basic tests.

To run:

npm run serve
# Connect to http://127.0.0.1:8080

Mocha Tests

This project provides Mocha tests which will exercise the library in a NodeJS context using require to include the module.

npm run test

API

BmiPercentileCalculator.convertDateToAgem

Calculates the number of months ago the given date was compared to now

convertDateToAgem(date: string, current: Date): number

• date: The date in YYYY-MM-DD format
• current: Date object to use as the current date (default Date.now())

BmiPercentileCalculator.metric

Takes various data points and generates information about that bmi and bmi percentile

BmiPercentileCalculator.metric(
	kgs: number,
	meters: number,
	sex: string,
	agem: number,
	optionalBMIData: object) : object`

• kgs: Weight in Kilograms
• meters: Height in meters
• sex: Biological sex. "f" for female and "m" for male
• agem: Age in months
• optionalBMIData: (optional) BMI data taken from the CDC calculator website

Returns: Object with the following fields:

• bmi: The calculated bmi
• percentile: The calculated bmi percentile
• overP95: The percentage over the 95th percentile. Present only if over the 97th percentile
• M: The median bmi for this person's age and sex categories,
• Z: The number of standard of deviations from the mean

BmiPercentileCalculator.english

Takes various data points and generates information about that bmi and bmi percentile using imperial (english) units

BmiPercentileCalculator.metric(
	lbs: number,
	inches: number,
	sex: string,
	agem: number,
	optionalBMIData: object) : object`

• lbs: Weight in pounds
• inches: Height in inches
• sex: Biological sex. "f" for female and "m" for male
• agem: Age in months
• optionalBMIData: (optional) BMI data taken from the CDC calculator website

Returns: See metric() above.

Version History

0.0.1 - Initial migration to a separate repo.