Function createHeatIndexFunction

source/helpers/math.ts:29–44

(numbers: number[])

 @returns function to calculate heat index of a given number
 */
export function createHeatIndexFunction(numbers: number[]): (value: number) => number {
	const steps = 10; // GH has 10 heat colors
	const min = Math.min(...numbers);
	const max = Math.max(...numbers);

	return (value: number) => {
		// Inverse linear interpolation figures out how far the value is between min & max
		const interp = Math.max(0, Math.min(1, inverseLinearInterpolation(min, max, value)));

		// Maps the [0.0, 1.0] value to [steps, 1]
		const floored = Math.floor(interp * steps);
		const heatIndex = Math.max(1, steps - floored);

		return heatIndex;
	};
}

export function randomArrayItem<T>(items: T[]): T {
	return items.at(Math.floor(Math.random() * items.length))!;