30-seconds-of-code/snippets/js/s/sum-powers-in-range.md

title, type, language, tags, cover, dateModified

title	type	language	tags	cover	dateModified
Sum of powers in range	snippet	javascript	math	boat-port	2020-10-22T20:24:30+03:00

Calculates the sum of the powers of all the numbers from start to end (both inclusive).

• Use Array.prototype.fill() to create an array of all the numbers in the target range.
• Use Array.prototype.map() and the exponent operator (**) to raise them to power and Array.prototype.reduce() to add them together.
• Omit the second argument, power, to use a default power of 2.
• Omit the third argument, start, to use a default starting value of 1.

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);

sumPower(10); // 385
sumPower(10, 3); // 3025
sumPower(10, 3, 5); // 2925