gossamer/weak_map

Types

WeakMap

A JS WeakMap whose keys are weakly held — entries are eligible for GC once the key has no other references. Mutable.

Keys must be objects (records, lists, tuples) or non-registered symbols (gossamer/symbol.new, not gossamer/symbol.for); set and from_list return an error otherwise. Has no size, iteration, or clear (those would expose GC timing).

Keys are matched by JS reference identity, not value equality — two equal-by-value tuples constructed separately are distinct keys.

See WeakMap on MDN.

pub type WeakMap(key, value)

Values

delete

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pub fn delete(
  from map: WeakMap(key, value),
  key key: key,
) -> WeakMap(key, value)

Mutates the map.

from_list

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pub fn from_list(
  entries: List(#(key, value)),
) -> Result(WeakMap(key, value), js_error.JsError)

Returns an error if any key in entries is invalid.

get

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pub fn get(
  from map: WeakMap(key, value),
  key key: key,
) -> Result(value, Nil)

Returns the value associated with the given key, or an error if not found.

has

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pub fn has(in map: WeakMap(key, value), key key: key) -> Bool

new

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pub fn new() -> WeakMap(key, value)

set

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pub fn set(
  in map: WeakMap(key, value),
  key key: key,
  value value: value,
) -> Result(WeakMap(key, value), js_error.JsError)

Mutates the map. Returns an error if key is invalid.