Dict

Type representing a dictionary of value 'a.

Returns the value at the provided key, if it exists. Returns an option.

Examples

RESCRIPT
let dict = Dict.fromArray([("someKey", "someValue")])

switch dict->Dict.get("someKey") {
| None => Console.log("Nope, didn't have the key.")
| Some(value) => Console.log(value)
}

set(dictionary, key, value) sets the value at the provided key to the provided value.

Examples

RESCRIPT
let dict = Dict.make()

dict->Dict.set("someKey", "someValue")

delete(dictionary, key) deletes the value at key, if it exists.

Examples

RESCRIPT
let dict = Dict.fromArray([("someKey", "someValue")])

dict->Dict.delete("someKey")

make() creates a new, empty dictionary.

Examples

RESCRIPT
let dict1: Dict.t<int> = Dict.make() // You can annotate the type of the values of your dict yourself if you want

let dict2 = Dict.make() // Or you can let ReScript infer it via usage.
dict2->Dict.set("someKey", 12)

fromArray(entries) creates a new dictionary from the provided array of key/value pairs.

Examples

RESCRIPT
let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])

fromIterator(entries) creates a new dictionary from the provided iterator of key/value pairs.

Examples

RESCRIPT
// Pretend we have an iterator of the correct shape
@val external someIterator: Iterator.t<(string, int)> = "someIterator"

let dict = Dict.fromIterator(someIterator) // Dict.t<int>

toArray(dictionary) returns an array of all the key/value pairs of the dictionary.

Examples

RESCRIPT
let dict = Dict.make()
dict->Dict.set("someKey", 1)
dict->Dict.set("someKey2", 2)
let asArray = dict->Dict.toArray
Console.log(asArray) // Logs `[["someKey", 1], ["someKey2", 2]]` to the console

keysToArray(dictionary) returns an array of all the keys of the dictionary.

Examples

RESCRIPT
let dict = Dict.make()
dict->Dict.set("someKey", 1)
dict->Dict.set("someKey2", 2)
let keys = dict->Dict.keysToArray
Console.log(keys) // Logs `["someKey", "someKey2"]` to the console

valuesToArray(dictionary) returns an array of all the values of the dictionary.

Examples

RESCRIPT
let dict = Dict.make()
dict->Dict.set("someKey", 1)
dict->Dict.set("someKey2", 2)
let values = dict->Dict.valuesToArray
Console.log(values) // Logs `[1, 2]` to the console

assign(dictionary1, dictionary2) shallowly merges dictionary2 into dictionary1, and returns dictionary1.

Beware this will mutate dictionary1. If you're looking for a way to copy a dictionary, check out Dict.copy.

Examples

RESCRIPT
let dict1 = Dict.make()
dict1->Dict.set("firstKey", 1)
Console.log(dict1->Dict.keysToArray) // Logs `["firstKey"]`

let dict2 = Dict.make()
dict2->Dict.set("someKey", 2)
dict2->Dict.set("someKey2", 3)

let dict1 = dict1->Dict.assign(dict2)

Console.log(dict1->Dict.keysToArray) // Logs `["firstKey", "someKey", "someKey2"]`

copy(dictionary) shallowly copies the provided dictionary to a new dictionary.

Examples

RESCRIPT
let dict = Dict.fromArray([("key1", "value1"), ("key2", "value2")])
let dict2 = dict->Dict.copy

// Both log `["key1", "key2"]` here.
Console.log2(dict->Dict.keysToArray, dict2->Dict.keysToArray)