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Big_map

A lazily deserialised map that is intended to store large amounts of data. Here, "lazily" means that storage is read or written per key on demand. Therefore there are no map, fold, and iter operations as there are in Map.

Compared to strict maps, which have a high upfront gas cost to deserialise all the data and then have cheaper access costs thereafter, lazily deserialised maps spread this cost out across each access, increasing the per-access gas costs, but providing a cheaper overall cost when only a small portion of a large dataset is needed.

cameligo
val empty : ('key, 'value) big_map
jsligo
let empty: big_map<'key, 'value>

Create an empty big map.

cameligo
type move = int * int
type register = (address, move) big_map

let empty : register = Big_map.empty
jsligo
type move = [int, int];
type register = big_map<address, move>;

let empty: register = Big_map.empty;
cameligo
val literal : ('key * 'value) list -> ('key, 'value) big_map
jsligo
let literal: (items: list<['key, 'value]>) => big_map<'key, 'value>

Create a non-empty big_map.

cameligo
let moves : register =
  Big_map.literal [
    (("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address), (1,2));
    (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address), (0,3))]
jsligo
let moves: register =
  Big_map.literal (list([
    [("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" as address), [1, 2]],
    [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), [0, 3]]]));
cameligo
val find_opt : 'key -> ('key, 'value) big_map -> 'value option
jsligo
let find_opt: (key: 'key, big_map: big_map <'key, 'value>) => option <'value>

Retrieve a value from a big map with the given key.

Because the key may be missing in the big map, the result is an optional value.

cameligo
let my_balance : move option =
  Big_map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) moves
jsligo
let my_balance: option <move> =
  Big_map.find_opt(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), moves);
cameligo
val mem : 'key -> ('key, 'value) big_map -> bool
jsligo
let mem: (key: 'key, big_map: big_map <'key, 'value>) => bool

Test whether a given key exists within a big map.

cameligo
let has_balance : bool =
  Big_map.mem ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) moves
jsligo
let has_balance: bool =
  Big_map.mem(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), moves);
cameligo
val update: 'key -> 'value option -> ('key, 'value) big_map -> ('key, 'value) big_map
jsligo
let update: (key: 'key, value: option<'value>, big_map: big_map<'key, 'value>) => big_map<'key, 'value>

Note: when None is used as a value, the value is removed from the big_map.

cameligo
let updated_map : register =
  Big_map.update
    ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) (Some (4,9)) moves
jsligo
let updated_map: register =
  Big_map.update
    (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), Some([4,9]), moves);
cameligo
val get_and_update : 'key -> 'value option -> ('key, 'value) big_map -> value option * ('key, 'value) big_map
jsligo
let get_and_update: (key: 'key, value: option<'value>, big_map: big_map<'key, 'value>) => [option<'value>, big_map<'key, 'value>]

Similar to update but it also returns the value that was previously stored in the big_map

cameligo
val add : 'key -> 'value -> ('key, 'value) big_map  -> ('key, 'value) big_map
jsligo
let add: (key: 'key, value: 'value, big_map: big_map<'key, 'value>) => big_map<'key, 'value>
cameligo
let add (m : register) : register =
  Big_map.add
    ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) (4,9) m
jsligo
let add = (m: register): register =>
  Big_map.add
    (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), [4,9], m);
cameligo
val remove: 'key -> ('key, 'value) big_map -> ('key, 'value) big_map
jsligo
let remove: (key: 'key, big_map: big_map<'key, 'value>) => big_map<'key, 'value>
cameligo
let updated_map : register =
  Big_map.remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) moves
jsligo
let updated_map_: register =
  Big_map.remove(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" as address), moves);
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