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fix: Remove ambiguity when Ok and Err value types are compatible. #70

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fix: Remove ambiguity when Ok and Err value types are compatible. #70

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48 changes: 24 additions & 24 deletions src/result.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -29,8 +29,8 @@ interface BaseResult<T, E> extends Iterable<T extends Iterable<infer U> ? U : ne
* Returns the contained `Ok` value, if does not exist. Throws an error if it does.
* @param msg the message to throw if Ok value.
*/
expectErr(msg: string): T;
expectErr(msg: string): E;

/**
* Returns the contained `Ok` value.
* Because this function may throw, its use is generally discouraged.
Expand Down Expand Up @@ -97,7 +97,7 @@ export class ErrImpl<E> implements BaseResult<never, E> {

readonly ok!: false;
readonly err!: true;
readonly val!: E;
readonly errVal!: E;

private readonly _stack!: string;

Expand All @@ -116,10 +116,10 @@ export class ErrImpl<E> implements BaseResult<never, E> {

this.ok = false;
this.err = true;
this.val = val;
this.errVal = val;

const stackLines = new Error().stack!.split('\n').slice(2);
if (stackLines && stackLines.length > 0 && stackLines[0].includes('ErrImpl')) {
if (stackLines && stackLines.length > 0 && stackLines[0]!.includes('ErrImpl')) {
stackLines.shift();
}

Expand All @@ -139,15 +139,15 @@ export class ErrImpl<E> implements BaseResult<never, E> {
}

expect(msg: string): never {
throw new Error(`${msg} - Error: ${toString(this.val)}\n${this._stack}`);
throw new Error(`${msg} - Error: ${toString(this.errVal)}\n${this._stack}`);
}

expectErr(_msg: string): E {
return this.val
return this.errVal
}

unwrap(): never {
throw new Error(`Tried to unwrap Error: ${toString(this.val)}\n${this._stack}`);
throw new Error(`Tried to unwrap Error: ${toString(this.errVal)}\n${this._stack}`);
}

map(_mapper: unknown): Err<E> {
Expand All @@ -159,15 +159,15 @@ export class ErrImpl<E> implements BaseResult<never, E> {
}

mapErr<E2>(mapper: (err: E) => E2): Err<E2> {
return new Err(mapper(this.val));
return new Err(mapper(this.errVal));
}

toOption(): Option<never> {
return None;
}

toString(): string {
return `Err(${toString(this.val)})`;
return `Err(${toString(this.errVal)})`;
}

get stack(): string | undefined {
Expand All @@ -187,13 +187,13 @@ export class OkImpl<T> implements BaseResult<T, never> {

readonly ok!: true;
readonly err!: false;
readonly val!: T;
readonly okVal!: T;

/**
* Helper function if you know you have an Ok<T> and T is iterable
*/
[Symbol.iterator](): Iterator<T extends Iterable<infer U> ? U : never> {
const obj = Object(this.val) as Iterable<any>;
const obj = Object(this.okVal) as Iterable<any>;

return Symbol.iterator in obj
? obj[Symbol.iterator]()
Expand All @@ -211,50 +211,50 @@ export class OkImpl<T> implements BaseResult<T, never> {

this.ok = true;
this.err = false;
this.val = val;
this.okVal = val;
}

/**
* @see unwrapOr
* @deprecated in favor of unwrapOr
*/
else(_val: unknown): T {
return this.val;
return this.okVal;
}

unwrapOr(_val: unknown): T {
return this.val;
return this.okVal;
}

expect(_msg: string): T {
return this.val;
return this.okVal;
}

expectErr(msg: string): never {
throw new Error(msg);
}

unwrap(): T {
return this.val;
return this.okVal;
}

map<T2>(mapper: (val: T) => T2): Ok<T2> {
return new Ok(mapper(this.val));
return new Ok(mapper(this.okVal));
}

andThen<T2>(mapper: (val: T) => Ok<T2>): Ok<T2>;
andThen<E2>(mapper: (val: T) => Err<E2>): Result<T, E2>;
andThen<T2, E2>(mapper: (val: T) => Result<T2, E2>): Result<T2, E2>;
andThen<T2, E2>(mapper: (val: T) => Result<T2, E2>): Result<T2, E2> {
return mapper(this.val);
return mapper(this.okVal);
}

mapErr(_mapper: unknown): Ok<T> {
return this;
}

toOption(): Option<T> {
return Some(this.val);
return Some(this.okVal);
}

/**
Expand All @@ -267,11 +267,11 @@ export class OkImpl<T> implements BaseResult<T, never> {
* (this is the `into_ok()` in rust)
*/
safeUnwrap(): T {
return this.val;
return this.okVal;
}

toString(): string {
return `Ok(${toString(this.val)})`;
return `Ok(${toString(this.okVal)})`;
}
}

Expand Down Expand Up @@ -302,7 +302,7 @@ export namespace Result {
const okResult = [];
for (let result of results) {
if (result.ok) {
okResult.push(result.val);
okResult.push(result.okVal);
} else {
return result as Err<ResultErrTypes<T>[number]>;
}
Expand All @@ -325,7 +325,7 @@ export namespace Result {
if (result.ok) {
return result as Ok<ResultOkTypes<T>[number]>;
} else {
errResult.push(result.val);
errResult.push(result.errVal);
}
}

Expand Down
18 changes: 9 additions & 9 deletions src/rxjs-operators/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -31,9 +31,9 @@ export function elseMap<T, E, E2>(mapper: (val: E) => E2): OperatorFunction<Resu
return source.pipe(
map((result) => {
if (result.err) {
return mapper(result.val);
return mapper(result.errVal);
} else {
return result.val;
return result.okVal;
}
}),
);
Expand All @@ -47,7 +47,7 @@ export function elseMapTo<T, E, E2>(value: E2): OperatorFunction<Result<T, E>, T
if (result.err) {
return value;
} else {
return result.val;
return result.okVal;
}
}),
);
Expand All @@ -67,7 +67,7 @@ export function resultSwitchMap<T, E, T2, E2>(
return source.pipe(
switchMap((result) => {
if (result.ok) {
return mapper(result.val);
return mapper(result.okVal);
} else {
return of(result);
}
Expand Down Expand Up @@ -96,7 +96,7 @@ export function resultMergeMap<T, E, T2, E2>(
return source.pipe(
mergeMap((result) => {
if (result.ok) {
return mapper(result.val);
return mapper(result.okVal);
} else {
return of(result);
}
Expand All @@ -116,7 +116,7 @@ export function filterResultOk<T, E>(): OperatorFunction<Result<T, E>, T> {
return (source) => {
return source.pipe(
filter((result): result is Ok<T> => result.ok),
map((result) => result.val),
map((result) => result.okVal),
);
};
}
Expand All @@ -125,7 +125,7 @@ export function filterResultErr<T, E>(): OperatorFunction<Result<T, E>, E> {
return (source) => {
return source.pipe(
filter((result): result is Err<E> => result.err),
map((result) => result.val),
map((result) => result.errVal),
);
};
}
Expand All @@ -135,7 +135,7 @@ export function tapResultErr<T, E>(tapFn: (err: E) => void): MonoTypeOperatorFun
return source.pipe(
tap((r) => {
if (!r.ok) {
tapFn(r.val);
tapFn(r.errVal);
}
}),
);
Expand All @@ -147,7 +147,7 @@ export function tapResultOk<T, E>(tapFn: (val: T) => void): MonoTypeOperatorFunc
return source.pipe(
tap((r) => {
if (r.ok) {
tapFn(r.val);
tapFn(r.okVal);
}
}),
);
Expand Down
6 changes: 3 additions & 3 deletions test/err.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -32,13 +32,13 @@ test('ok, err, and val', () => {
expect(err.ok).toBe(false);
assert<typeof err.ok>(false);

expect(err.val).toBe(32);
eq<typeof err.val, number>(true);
expect(err.errVal).toBe(32);
eq<typeof err.errVal, number>(true);
});

test('static EMPTY', () => {
expect(Err.EMPTY).toBeInstanceOf(Err);
expect(Err.EMPTY.val).toBe(undefined);
expect(Err.EMPTY.errVal).toBe(undefined);
eq<typeof Err.EMPTY, Err<void>>(true);
});

Expand Down
6 changes: 3 additions & 3 deletions test/ok.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -33,13 +33,13 @@ test('ok, err, and val', () => {
expect(err.ok).toBe(true);
assert<typeof err.ok>(true);

expect(err.val).toBe(32);
eq<typeof err.val, number>(true);
expect(err.okVal).toBe(32);
eq<typeof err.okVal, number>(true);
});

test('static EMPTY', () => {
expect(Ok.EMPTY).toBeInstanceOf(Ok);
expect(Ok.EMPTY.val).toBe(undefined);
expect(Ok.EMPTY.okVal).toBe(undefined);
eq<typeof Ok.EMPTY, Ok<void>>(true);
});

Expand Down
5 changes: 2 additions & 3 deletions test/result.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,7 @@ test('Result.all', () => {
eq<typeof all1, Result<[number, boolean], never>>(true);

const all3 = Result.all(err0, err1);
expect(all3).toMatchResult(Err(err0.val));
expect(all3).toMatchResult(Err(err0.errVal));
eq<typeof all3, Result<[never, never], symbol | Error>>(true);

const all4 = Result.all(...([] as Result<string, number>[]));
Expand Down Expand Up @@ -143,7 +143,7 @@ test('Result.any', () => {
eq<typeof any1, Result<number | boolean, [never, never]>>(true);

const any3 = Result.any(err0, err1);
expect(any3).toMatchResult(Err([err0.val, err1.val]));
expect(any3).toMatchResult(Err([err0.errVal, err1.errVal]));
eq<typeof any3, Result<never, [symbol, Error]>>(true);

const any4 = Result.any(...([] as Result<string, number>[]));
Expand Down Expand Up @@ -189,7 +189,6 @@ test('Result.wrapAsync', async () => {

const c = await Result.wrapAsync<number, string>(() => {
throw 'thrown before promise';
return Promise.resolve(3);
});

expect(c).toMatchResult(Err('thrown before promise'));
Expand Down
36 changes: 26 additions & 10 deletions test/util.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -25,18 +25,25 @@ expect.extend({
let pass = true;
try {
expect(received.ok).toBe(result.ok);

if (received.val !== result.val) {
expect(received.val).toMatchObject(result.val);
if (received.ok && result.ok) {
if (received.okVal !== result.okVal) {
expect(received.okVal).toMatchObject(result.okVal);
}
} else if (received.err && result.err) {
if (received.errVal !== result.errVal) {
expect(received.errVal).toMatchObject(result.errVal);
}
} else {
pass = false;
}
} catch (e) {
pass = false;
}

const type = received.ok ? 'Ok' : 'Err';
const expectedType = received.ok ? 'Ok' : 'Err';
const val = JSON.stringify(received.val);
const expectedVal = JSON.stringify(result.val);
const val = received.ok ? JSON.stringify(received.okVal) : JSON.stringify(received.errVal);
const expectedVal = result.ok ? JSON.stringify(result.okVal): JSON.stringify(result.errVal);

return {
message: () => `expected ${type}(${val}) ${pass ? '' : 'not '}to equal ${expectedType}(${expectedVal})`,
Expand All @@ -51,18 +58,27 @@ expect.extend({
obs.subscribe((val) => (received = val)).unsubscribe();

expect(received?.ok).toBe(result.ok);

if (received?.val !== result.val) {
expect(received?.val).toMatchObject(result.val);
if (received && received.ok && result.ok) {
if (received.okVal !== result.okVal) {
expect(received.okVal).toMatchObject(result.okVal);
}
} else if (received && received.err && result.err) {
if (received.errVal !== result.errVal) {
expect(received.errVal).toMatchObject(result.errVal);
}
} else {
pass = false;
}


} catch (e) {
pass = false;
}

const type = received?.ok ? 'Ok' : 'Err';
const expectedType = received?.ok ? 'Ok' : 'Err';
const val = JSON.stringify(received?.val);
const expectedVal = JSON.stringify(result.val);
const val = received?.ok ? JSON.stringify(received.okVal) : JSON.stringify(received?.errVal);
const expectedVal = result.ok ? JSON.stringify(result.okVal): JSON.stringify(result.errVal);

return {
message: () => `expected ${type}(${val}) ${pass ? '' : 'not '}to equal ${expectedType}(${expectedVal})`,
Expand Down