30-seconds-of-code/snippets/sumPower.md

title, tags, firstSeen, lastUpdated

title	tags	firstSeen	lastUpdated
sumPower	math,intermediate	2018-01-01T15:49:25+02:00	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