Find the closest number from an array

Return the item nearest to a target.

JavaScript Version 1.0.0 · MIT · .md

function closest({ values, target }) { return values.reduce((best, value) => (Math.abs(value - target) < Math.abs(best - target) ? value : best)); }

Input & expected output

{
  "values": [
    29,
    87,
    8,
    78,
    97,
    20,
    75,
    33,
    24,
    17
  ],
  "target": 50
}

33

The edge case

{
  "values": [
    10,
    20
  ],
  "target": 15
}

10

Know the limits

• The first candidate wins on ties, as the edge case shows. The lab requires at least one number.

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.