bs-js-collections

bs-js-collections

Bindings to primitive JavaScript Set and Map types for BuckleScript/ReScript, plus some useful bells and whistles.

Examples

Sets

let myIntSet = JsSet.empty();
[|1, 2, 3|]->Belt.Array.forEach(myIntSet->JsSet.add);
myIntSet->JsSet.delete(1);
Js.log(myIntSet->JsSet.size); // 2

Maps

let myStringMap = JsMap.fromArray([|("x", 1), ("y", 2)|]);
myStringMap->JsMap.delete("x");
Js.log(myStringMap->JsMap.size); // 1
Js.log(myStringMap->JsMap.has("y")); // true
Js.log(myStringMap->Js.Map.get("y")); // 2

See unit tests for more examples. In addition a number of higher-level utility functions are included, such as map, keep, keepMap, etc. In general we try to follow naming conventions similar to Belt and a pipe-first style. Note that many of these functions still require tests, so use with caution and your own testing.

Usable types

One of the advantages of JsMap.t over Js.Dict.t is to allow arbitrary key types (e.g. numbers). Similarly for the values allowable in JsSet.t. The compiler will set values and map keys to be any type, but in practice only certain types will work. In particular, it must be a type at runtime that JavaScript is able to handle.

The rule of thumb is that for map keys and set values, it must be a type which, at runtime, takes the form of an int, a string, a boolean, etc. This means that most enums are fine, as are opaque wrapper types.

Do not use records, lists, arrays, tuples, etc.

Avoid optional types in general or at the least provide extra testing if it's unavoidable.

Commands/scripts

yarn re:build
yarn re:clean
yarn re:watch