Get all subsets of an array

Build the power set, smallest subsets first.

JavaScript Version 1.0.0 · MIT · .md

function getSubsets(values) { return values.reduce((subsets, value) => subsets.concat(subsets.map(subset => [...subset, value])), [[]]); }

Input & expected output

[
  "a",
  "b",
  "c"
]

[
  [],
  [
    "a"
  ],
  [
    "b"
  ],
  [
    "a",
    "b"
  ],
  [
    "c"
  ],
  [
    "a",
    "c"
  ],
  [
    "b",
    "c"
  ],
  [
    "a",
    "b",
    "c"
  ]
]

The edge case

[]

[
  []
]

Know the limits

• The result has 2^n subsets, so the lab accepts at most 10 values (1,024 subsets).

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.