to-typed
Version:
Type-guards, casts and converts unknowns into typed values
63 lines • 1.9 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.Maybe = void 0;
class MaybeBase {
constructor(data) {
this.data = data;
}
static just(value) {
return new MaybeBase({ hasValue: true, value });
}
static nothing(error = MaybeBase.defaultError) {
return new MaybeBase({ hasValue: false, error });
}
get hasValue() {
return this.data.hasValue;
}
get value() {
return this.else(() => undefined);
}
get error() {
return this.read(() => undefined, e => e);
}
static all(maybes) {
const result = (Array.isArray(maybes) ? [] : {});
const entries = Object.entries(maybes);
for (let [k, v] of entries) {
if (v.hasValue)
result[k] = v.value;
else
return MaybeBase.nothing(v.error);
}
return MaybeBase.just(result);
}
static any(maybes) {
const result = [];
for (let maybe of maybes) {
if (maybe.hasValue)
result.push(maybe.value);
}
return result;
}
read(ifValue, ifNothing) {
return this.data.hasValue ? ifValue(this.data.value) : ifNothing ? ifNothing(this.data.error) : undefined;
}
bind(next) {
return this.read(next, MaybeBase.nothing);
}
map(next) {
return this.bind(value => MaybeBase.just(next(value)));
}
or(right) {
return this.read(t => MaybeBase.just(t), () => right);
}
else(getAlt) {
return this.read((t) => t, e => getAlt(e));
}
elseThrow(getError = e => e) {
return this.read((t) => t, e => { throw getError(e); });
}
}
MaybeBase.defaultError = new Error("Maybe has no value");
exports.Maybe = MaybeBase;
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