Get the average of an array

Divide the sum by the count.

JavaScript Version 1.0.0 · MIT · .md

function average(values) { return values.reduce((sum, value) => sum + value, 0) / values.length; }

Input & expected output

[
  4,
  8,
  3
]

5

The edge case

[
  0.1,
  0.2
]

0.15000000000000002

Know the limits

• Floating-point sums are approximate, as the edge case shows.
• An empty array divides by zero and returns NaN (null in JSON); check the length first.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Clone an array — Create a new array without copying the objects inside it.
• Remove duplicate values — Keep the first occurrence of each value, in its original order.
• Flatten a nested array — Turn a nested array into one sequence of values.