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fix: Make handling of async iterables consistent #3602

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Merged
daffl merged 1 commit into from
Aug 15, 2025
+32 −7
Merged

fix: Make handling of async iterables consistent #3602

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10 changes: 7 additions & 3 deletions packages/feathers/fixtures/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -19,10 +19,14 @@ export class ResponseTestService {
})
}

async *get(id: string) {
for (let i = 1; i <= 5; i++) {
yield { message: `Hello ${id} ${i}` }
async get(id: string) {
const generator = async function* () {
for (let i = 1; i <= 5; i++) {
yield { message: `Hello ${id} ${i}` }
}
}

return generator()
}

async options(_params: Params) {
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6 changes: 3 additions & 3 deletions packages/feathers/src/client/fetch.test.ts
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Expand Up @@ -110,11 +110,11 @@ describe('fetch REST connector', function () {
await expect(() => service.internalMethod({})).rejects.toThrow(MethodNotAllowed)
})

it('supports event streams', async () => {
it('supports async iterable streams', async () => {
const messages: any[] = []
const stream = await app.service('test').get('test')

// TODO investigate need for additional await
for await (const data of await app.service('test').get('test')) {
for await (const data of stream) {
messages.push(data)
}

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13 changes: 13 additions & 0 deletions packages/feathers/src/hooks/function.test.ts
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Expand Up @@ -485,4 +485,17 @@ describe('feathers/hooks function', () => {
assert.strictEqual(await fn('Dave'), 'Hello Dave')
assert.strictEqual(await fn(), 'Hello Bertho')
})

it('returning an async iterator directly errors', () => {
const iterable = async function* () {
yield 'Hello'
yield 'World'
}

const fn = hooks(iterable, [])

expect(() => fn()).rejects.toThrow(
'Function must return a Promise that resolves to an async iterable, not the iterable directly'
)
})
})
10 changes: 9 additions & 1 deletion packages/feathers/src/hooks/hooks.ts
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Expand Up @@ -43,7 +43,15 @@ export function functionHooks<F>(fn: F, managerOrMiddleware: HookOptions) {
// Runs the actual original method if `ctx.result` is not already set
hookChain.push((ctx, next) => {
if (!Object.prototype.hasOwnProperty.call(context, 'result')) {
return Promise.resolve(original.apply(this, ctx.arguments)).then((result) => {
const returnValue = original.apply(this, ctx.arguments)

if (returnValue[Symbol.asyncIterator]) {
throw new Error(
'Function must return a Promise that resolves to an async iterable, not the iterable directly'
)
}

return Promise.resolve(returnValue).then((result) => {
ctx.result = result

return next()
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