45 lines
1.4 KiB
JavaScript
45 lines
1.4 KiB
JavaScript
/**
|
|
* A `Functor` is a type constructor which supports a mapping operation `map`.
|
|
*
|
|
* `map` can be used to turn functions `a -> b` into functions `f a -> f b` whose argument and return types use the type
|
|
* constructor `f` to represent some computational context.
|
|
*
|
|
* Instances must satisfy the following laws:
|
|
*
|
|
* 1. Identity: `F.map(fa, a => a) <-> fa`
|
|
* 2. Composition: `F.map(fa, a => bc(ab(a))) <-> F.map(F.map(fa, ab), bc)`
|
|
*
|
|
* @since 2.0.0
|
|
*/
|
|
import { pipe } from './function';
|
|
export function map(F, G) {
|
|
return function (f) { return function (fa) { return F.map(fa, function (ga) { return G.map(ga, f); }); }; };
|
|
}
|
|
export function flap(F) {
|
|
return function (a) { return function (fab) { return F.map(fab, function (f) { return f(a); }); }; };
|
|
}
|
|
export function bindTo(F) {
|
|
return function (name) { return function (fa) { return F.map(fa, function (a) {
|
|
var _a;
|
|
return (_a = {}, _a[name] = a, _a);
|
|
}); }; };
|
|
}
|
|
function let_(F) {
|
|
return function (name, f) { return function (fa) { return F.map(fa, function (a) {
|
|
var _a;
|
|
return Object.assign({}, a, (_a = {}, _a[name] = f(a), _a));
|
|
}); }; };
|
|
}
|
|
export {
|
|
/**
|
|
* @since 2.13.0
|
|
*/
|
|
let_ as let };
|
|
/** @deprecated */
|
|
export function getFunctorComposition(F, G) {
|
|
var _map = map(F, G);
|
|
return {
|
|
map: function (fga, f) { return pipe(fga, _map(f)); }
|
|
};
|
|
}
|