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Update error handling logic to preserve custom error objects #48

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Merged
merged 1 commit into from
Mar 31, 2020
Merged

Update error handling logic to preserve custom error objects #48

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10 changes: 6 additions & 4 deletions API_DOCS.md
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Original file line number Diff line number Diff line change
Expand Up @@ -38,12 +38,14 @@ getLoaders(resources[, options])

- **`errorHandler`**

(Optional) Provide a function to wrap the underlying resource call. Useful if you want to handle 'expected' errors (e.g. 4xxs, 5xxs) before handing over to the resolver method.
(Optional) Provide a function to wrap the underlying resource call. Useful if you want to handle 'expected' errors or rejected promises from the resource function (e.g. 4xxs, 5xxs) before handing over to the resolver method.

Must return an Error object.

**Interface:**

```js
errorHandler(resourcePath: Array<string>, error: Error): Promise<Error>
(resourcePath: $ReadOnlyArray<string>, error: any): Promise<Error>,
```

- **`resourceMiddleware`**
Expand All @@ -58,7 +60,7 @@ getLoaders(resources[, options])
**Interface**:

```js
before(resourcePath: Array<string>, resourceArgs: T): Promise<T>
(resourcePath: $ReadOnlyArray<string>, resourceArgs: T): Promise<T>
```

- **`after`**
Expand All @@ -68,7 +70,7 @@ getLoaders(resources[, options])
**Interface**:

```js
after(resourcePath: Array<string>, response: T): Promise<T>
(resourcePath: $ReadOnlyArray<string>, response: T): Promise<T>
```

### Example
Expand Down
230 changes: 164 additions & 66 deletions __tests__/implementation.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -292,69 +292,6 @@ test('batch endpoint (multiple requests)', async () => {
});
});

test('batch endpoint that throws errors', async () => {
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Collaborator Author

@magicmark magicmark Mar 31, 2020

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Removing this since it's the same test as

dataloader-codegen/__tests__/implementation.test.js

Line 421 in 3c4bcb1

test('batch endpoint (multiple requests, default error handling)', async () => {

const config = {
resources: {
foo: {
isBatchResource: true,
docsLink: 'example.com/docs/bar',
batchKey: 'foo_ids',
newKey: 'foo_id',
},
},
};

const resources = {
foo: ({ foo_ids, include_extra_info }) => {
if (_.isEqual(foo_ids, [1, 3])) {
expect(include_extra_info).toBe(false);
throw new Error('yikes');
}

if (_.isEqual(foo_ids, [2, 4, 5])) {
expect(include_extra_info).toBe(true);
return Promise.resolve([
{
foo_id: 2,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 4,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 5,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
]);
}
},
};

await createDataLoaders(config, async getLoaders => {
const loaders = getLoaders(resources);

const results = await loaders.foo.loadMany([
{ foo_id: 1, include_extra_info: false },
{ foo_id: 2, include_extra_info: true },
{ foo_id: 3, include_extra_info: false },
{ foo_id: 4, include_extra_info: true },
{ foo_id: 5, include_extra_info: true },
]);

expect(results).toMatchObject([
expect.toBeError(/yikes/),
{ foo_id: 2, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
expect.toBeError(/yikes/),
{ foo_id: 4, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
{ foo_id: 5, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
]);
});
});

test('batch endpoint that rejects', async () => {
const config = {
resources: {
Expand Down Expand Up @@ -408,6 +345,7 @@ test('batch endpoint that rejects', async () => {
{ foo_id: 5, include_extra_info: true },
]);

// NonError comes from the default error handler which uses ensure-error
expect(results).toMatchObject([
expect.toBeError(/yikes/, 'NonError'),
{ foo_id: 2, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
Expand All @@ -434,7 +372,7 @@ test('batch endpoint (multiple requests, default error handling)', async () => {
foo: ({ foo_ids, include_extra_info }) => {
if (_.isEqual(foo_ids, [1, 3])) {
expect(include_extra_info).toBe(false);
return new Error('yikes');
throw new Error('yikes');
}

if (_.isEqual(foo_ids, [2, 4, 5])) {
Expand Down Expand Up @@ -482,8 +420,9 @@ test('batch endpoint (multiple requests, default error handling)', async () => {
});

test('batch endpoint (multiple requests, custom error handling)', async () => {
function errorHandler(resourcePath, error) {
async function errorHandler(resourcePath, error) {
expect(resourcePath).toEqual(['foo']);
expect(error.message).toBe('yikes');
return new Error('hello from custom error handler');
}

Expand All @@ -502,7 +441,7 @@ test('batch endpoint (multiple requests, custom error handling)', async () => {
foo: ({ foo_ids, include_extra_info }) => {
if (_.isEqual(foo_ids, [1, 3])) {
expect(include_extra_info).toBe(false);
return new Error('yikes');
throw new Error('yikes');
}

if (_.isEqual(foo_ids, [2, 4, 5])) {
Expand Down Expand Up @@ -999,3 +938,162 @@ test('middleware can transform the request args and the resource response', asyn
]);
});
});

test('returning custom errors from error handler is supported', async () => {
class MyCustomError extends Error {
constructor(...args) {
super(...args);
this.name = this.constructor.name;
this.foo = 'bar';
Error.captureStackTrace(this, MyCustomError);
}
}

function errorHandler(resourcePath, error) {
expect(resourcePath).toEqual(['foo']);
expect(error.message).toBe('yikes');
return new MyCustomError('hello from custom error object');
}

const config = {
resources: {
foo: {
isBatchResource: true,
docsLink: 'example.com/docs/bar',
batchKey: 'foo_ids',
newKey: 'foo_id',
},
},
};

const resources = {
foo: ({ foo_ids, include_extra_info }) => {
if (_.isEqual(foo_ids, [1, 3])) {
expect(include_extra_info).toBe(false);
throw new Error('yikes');
}

if (_.isEqual(foo_ids, [2, 4, 5])) {
expect(include_extra_info).toBe(true);
return Promise.resolve([
{
foo_id: 2,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 4,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 5,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
]);
}
},
};

await createDataLoaders(config, async getLoaders => {
const loaders = getLoaders(resources, { errorHandler });

const results = await loaders.foo.loadMany([
{ foo_id: 1, include_extra_info: false },
{ foo_id: 2, include_extra_info: true },
{ foo_id: 3, include_extra_info: false },
{ foo_id: 4, include_extra_info: true },
{ foo_id: 5, include_extra_info: true },
]);

expect(results).toMatchObject([
expect.toBeError(/hello from custom error object/, 'MyCustomError'),
{ foo_id: 2, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
expect.toBeError(/hello from custom error object/, 'MyCustomError'),
{ foo_id: 4, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
{ foo_id: 5, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
]);

expect(results[0]).toHaveProperty('foo', 'bar');
expect(results[2]).toHaveProperty('foo', 'bar');
});
});

test('bail if errorHandler does not return an error', async () => {
class MyCustomError extends Error {
constructor(...args) {
super(...args);
this.name = this.constructor.name;
this.foo = 'bar';
Error.captureStackTrace(this, MyCustomError);
}
}

function errorHandler(resourcePath, error) {
expect(resourcePath).toEqual(['foo']);
expect(error.message).toBe('yikes');
return 'not an Error object';
}

const config = {
resources: {
foo: {
isBatchResource: true,
docsLink: 'example.com/docs/bar',
batchKey: 'foo_ids',
newKey: 'foo_id',
},
},
};

const resources = {
foo: ({ foo_ids, include_extra_info }) => {
if (_.isEqual(foo_ids, [1, 3])) {
expect(include_extra_info).toBe(false);
throw new Error('yikes');
}

if (_.isEqual(foo_ids, [2, 4, 5])) {
expect(include_extra_info).toBe(true);
return Promise.resolve([
{
foo_id: 2,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 4,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
{
foo_id: 5,
foo_value: 'greetings',
extra_stuff: 'lorem ipsum',
},
]);
}
},
};

await createDataLoaders(config, async getLoaders => {
const loaders = getLoaders(resources, { errorHandler });

const results = await loaders.foo.loadMany([
{ foo_id: 1, include_extra_info: false },
{ foo_id: 2, include_extra_info: true },
{ foo_id: 3, include_extra_info: false },
{ foo_id: 4, include_extra_info: true },
{ foo_id: 5, include_extra_info: true },
]);

expect(results).toMatchObject([
expect.toBeError(/errorHandler did not return an Error object. Instead, got string: 'not an Error object'/),
{ foo_id: 2, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
expect.toBeError(/errorHandler did not return an Error object. Instead, got string: 'not an Error object'/),
{ foo_id: 4, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
{ foo_id: 5, foo_value: 'greetings', extra_stuff: 'lorem ipsum' },
]);
});
});
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