Partial sum array

JavaScript, Math · Jan 30, 2022

Creates an array of partial sums.

  • Use Array.prototype.reduce(), initialized with an empty array accumulator to iterate over nums.
  • Use Array.prototype.slice() to get the previous partial sum or 0 and add the current element to it.
  • Use the spread operator (...) to add the new partial sum to the accumulator array containing the previous sums.
const accumulate = (...nums) =>
  nums.reduce((acc, n) => [...acc, n + (acc.slice(-1)[0] || 0)], []);

accumulate(1, 2, 3, 4); // [1, 3, 6, 10]
accumulate(...[1, 2, 3, 4]); // [1, 3, 6, 10]

More like this

  • Mapped array sum

    Calculates the sum of an array, after mapping each element to a value using the provided function.

    JavaScript, Math · Nov 3, 2020

  • Cross product of arrays

    Creates a new array out of the two supplied by creating each possible pair from the arrays.

    JavaScript, Math · Oct 22, 2020

  • Array sum

    Calculates the sum of two or more numbers/arrays.

    JavaScript, Math · Oct 22, 2020