ts-utls
Version:
Utilities for TypeScript library
184 lines (180 loc) • 5.93 kB
JavaScript
"use strict";
/*
MIT License
Copyright (c) 2022 Cyril Dever
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Maybe = exports.None = exports.Some = void 0;
const _1 = require(".");
const __1 = require("..");
/**
* Implement a `Maybe` instance
*
* @tparam `<T>` The type parameter
* @param {boolean} isValue Set to `true` is passing an actual value of type `T`
* @param {T} val The value
*/
class MaybeImpl {
constructor(isValue, val) {
this.hasValue = isValue;
if (isValue && isNothing(val)) {
throw new Error('Can not create Some with illegal value: ' + val + '.');
}
this.val = val;
}
/* Monad implementation */
ap(maybeFn) {
if (this.hasValue) {
const value = this.val;
return maybeFn.map(function (fn) {
return fn(value);
});
}
else {
return (0, exports.None)();
}
}
bind(bindFn) {
return this.hasValue ? bindFn(this.val) : (0, exports.None)();
}
flatMap(flatMapFn) {
return this.hasValue ? flatMapFn(this.val) : (0, exports.None)();
}
chain(chainFn) {
return this.hasValue ? chainFn(this.val) : (0, exports.None)();
}
join() {
return this.flatMap(_1.idFunction);
}
map(mapFn) {
try {
const m = mapFn(this.val);
return m !== undefined ? (0, exports.Some)(m) : (0, exports.None)();
}
catch (_) { // eslint-disable-line @typescript-eslint/no-unused-vars
return (0, exports.None)();
}
}
takeLeft(m) {
// eslint-disable-next-line @typescript-eslint/no-unused-vars
return apply2(this, m, function (a, b) {
return a;
});
}
takeRight(m) {
// eslint-disable-next-line @typescript-eslint/no-unused-vars
return apply2(this, m, function (a, b) {
return b;
});
}
/* Maybe specifics */
cata(none, some) {
return this.isSome() ? some(this.val) : none();
}
filter(fn) {
const self = this; // eslint-disable-line @typescript-eslint/no-this-alias
return self.flatMap(function (a) {
return a !== null && fn(a) ? (0, exports.Some)(self.val) : (0, exports.None)();
});
}
fold(defaultValue) {
const self = this; // eslint-disable-line @typescript-eslint/no-this-alias
return function (fn) {
return self.isSome() ? fn(self.val) : defaultValue;
};
}
forEach(fn) {
return this.cata(_1.noop, fn);
}
getOrElse(val) {
return this.hasValue ? this.val : val;
}
orElse(maybe) {
return this.isSome() ? this : maybe;
}
orSome(otherValue) {
return this.hasValue ? this.val : otherValue;
}
orNull() {
return this.orSome(null);
}
orUndefined() {
return this.orSome(undefined);
}
isNone() {
return !this.isSome();
}
isSome() {
return this.hasValue;
}
some() {
if (this.hasValue) {
return this.val;
}
else {
throw new Error('Cannot call .some() on a None.');
}
}
toArray() {
const maybeArr = this.map((val) => [val]);
return maybeArr.isSome()
? maybeArr.some()
: [];
}
toEither(failVal) {
return this.isSome() ? (0, __1.Right)(this.val) : (0, __1.Left)(failVal);
}
toList() {
return this.hasValue ? __1.List.of(this.val) : (0, __1.Nil)();
}
}
const apply2 = (a1, a2, f) =>
// eslint-disable-next-line @typescript-eslint/no-unsafe-argument
a2.ap(a1.map(curry(f, [])));
const curry = (fn, args) => {
return function () {
const args1 = args.concat((0, _1.getArgs)(arguments)); // eslint-disable-line prefer-rest-params
// eslint-disable-next-line @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-member-access
return args1.length >= fn.length ?
// eslint-disable-next-line prefer-spread, @typescript-eslint/no-unsafe-member-access, @typescript-eslint/no-unsafe-call
fn.apply(null, args1.slice(0, args1.length)) :
curry(fn, args1);
};
};
const isNothing = (val) => val === null || val === undefined;
const Some = (val) => new MaybeImpl(true, val);
exports.Some = Some;
const None = () => new MaybeImpl(false, null);
exports.None = None;
const fromNull = (val) => {
return isNothing(val) ? (0, exports.None)() : (0, exports.Some)(val);
};
const fromUndefined = (val) => {
return val === undefined ? (0, exports.None)() : (0, exports.Some)(val);
};
const toList = (val) => {
return val.toList();
};
exports.Maybe = {
fromNull,
fromUndefined,
None: exports.None,
Some: exports.Some,
toList
};
//# sourceMappingURL=maybe.js.map