gossamer/set

JavaScript Set bindings for interop with APIs that produce or consume a Set. Treated as a transit type: bridge to gleam/set.Set via to_set and operate on the canonical Gleam surface for transformations, then from_set back when handing off to JavaScript. The non-mutating reads (size, has, values) stay for one-shot interop without round-tripping through gleam/set.Set.

Types

Set

</>

A JavaScript Set, holding unique values of any type and preserving insertion order.

For most Gleam use cases, prefer gleam/set.Set. This binding exists for interop with JavaScript code that expects a Set; bridge with to_set / from_set and operate on the gleam/set.Set surface for transformations.

Object values (records, lists, tuples) are matched by JavaScript reference identity, not by Gleam value equality — two equal-by-value tuples constructed separately are distinct values. Primitive values (Int, Float, String, Bool) use value equality.

See Set on MDN.

pub type Set(value)

Values

from_list

</>

pub fn from_list(values: List(value)) -> Set(value)

Creates a Set from a list of values. Duplicate values appear once.

from_set

</>

pub fn from_set(values: set.Set(value)) -> Set(value)

Creates a Set from a gleam/set.Set.

has

</>

pub fn has(in values: Set(value), value value: value) -> Bool

Returns whether the Set contains the given value.

new

</>

pub fn new() -> Set(value)

Creates an empty Set.

size

</>

pub fn size(values: Set(value)) -> Int

The number of values in the Set.

to_set

</>

pub fn to_set(values: Set(value)) -> set.Set(value)

Converts the Set to a gleam/set.Set. Insertion order is preserved as gleam/set.Set insertion order.

values

</>

pub fn values(values: Set(value)) -> yielder.Yielder(value)

Returns the values of the Set in insertion order.