feat: accept browser readable streams as input (#21)

N.b you can't read from a browser reaable stream repeatedly as the
first call to `stream.getReader` locks the reader to the first
invocation so I had to change all the test data to be functions
that reutrn a new instance of the data.

Author: achingbrain

src/files/normalise-input.js

@@ -99,6 +99,15 @@ module.exports = function normaliseInput (input) {
     })()
   }
 
+  // window.ReadableStream
+  if (typeof input.getReader === 'function') {
+    return (async function * () {
+      for await (const obj of browserStreamToIt(input)) {
+        yield toFileObject(obj)
+      }
+    })()
+  }
+
   // AsyncIterable<?>
   if (input[Symbol.asyncIterator]) {
     return (async function * () {
@@ -171,6 +180,11 @@ function toAsyncIterable (input) {
     return blobToAsyncGenerator(input)
   }
 
+  // Browser stream
+  if (typeof input.getReader === 'function') {
+    return browserStreamToIt(input)
+  }
+
   // Iterator<?>
   if (input[Symbol.iterator]) {
     return (async function * () { // eslint-disable-line require-await
@@ -232,14 +246,14 @@ function isFileObject (obj) {
 function blobToAsyncGenerator (blob) {
   if (typeof blob.stream === 'function') {
     // firefox < 69 does not support blob.stream()
-    return streamBlob(blob)
+    return browserStreamToIt(blob.stream())
   }
 
   return readBlob(blob)
 }
 
-async function * streamBlob (blob) {
-  const reader = blob.stream().getReader()
+async function * browserStreamToIt (stream) {
+  const reader = stream.getReader()
 
   while (true) {
     const result = await reader.read()

test/files/normalise-input.spec.js

@@ -12,16 +12,24 @@ const globalThis = require('../../src/globalthis')
 chai.use(dirtyChai)
 const expect = chai.expect
 
-const STRING = 'hello world'
-const BUFFER = Buffer.from(STRING)
-const ARRAY = Array.from(BUFFER)
-const TYPEDARRAY = Uint8Array.from(ARRAY)
+const STRING = () => 'hello world'
+const BUFFER = () => Buffer.from(STRING())
+const ARRAY = () => Array.from(BUFFER())
+const TYPEDARRAY = () => Uint8Array.from(ARRAY())
 let BLOB
+let WINDOW_READABLE_STREAM
 
 if (supportsFileReader) {
-  BLOB = new globalThis.Blob([
-    STRING
+  BLOB = () => new globalThis.Blob([
+    STRING()
   ])
+
+  WINDOW_READABLE_STREAM = () => new globalThis.ReadableStream({
+    start (controller) {
+      controller.enqueue(BUFFER())
+      controller.close()
+    }
+  })
 }
 
 async function verifyNormalisation (input) {
@@ -31,7 +39,7 @@ async function verifyNormalisation (input) {
     chai.assert.fail('Content should have been an iterable or an async iterable')
   }
 
-  expect(await all(input[0].content)).to.deep.equal([BUFFER])
+  expect(await all(input[0].content)).to.deep.equal([BUFFER()])
   expect(input[0].path).to.equal('')
 }
 
@@ -54,56 +62,56 @@ function asyncIterableOf (thing) {
 describe('normalise-input', function () {
   function testInputType (content, name, isBytes) {
     it(name, async function () {
-      await testContent(content)
+      await testContent(content())
     })
 
     if (isBytes) {
       it(`Iterable<${name}>`, async function () {
-        await testContent(iterableOf(content))
+        await testContent(iterableOf(content()))
       })
 
       it(`AsyncIterable<${name}>`, async function () {
-        await testContent(asyncIterableOf(content))
+        await testContent(asyncIterableOf(content()))
       })
     }
 
     it(`{ path: '', content: ${name} }`, async function () {
-      await testContent({ path: '', content })
+      await testContent({ path: '', content: content() })
     })
 
     if (isBytes) {
       it(`{ path: '', content: Iterable<${name}> }`, async function () {
-        await testContent({ path: '', content: iterableOf(content) })
+        await testContent({ path: '', content: iterableOf(content()) })
       })
 
       it(`{ path: '', content: AsyncIterable<${name}> }`, async function () {
-        await testContent({ path: '', content: asyncIterableOf(content) })
+        await testContent({ path: '', content: asyncIterableOf(content()) })
       })
     }
 
     it(`Iterable<{ path: '', content: ${name} }`, async function () {
-      await testContent(iterableOf({ path: '', content }))
+      await testContent(iterableOf({ path: '', content: content() }))
     })
 
     it(`AsyncIterable<{ path: '', content: ${name} }`, async function () {
-      await testContent(asyncIterableOf({ path: '', content }))
+      await testContent(asyncIterableOf({ path: '', content: content() }))
     })
 
     if (isBytes) {
       it(`Iterable<{ path: '', content: Iterable<${name}> }>`, async function () {
-        await testContent(iterableOf({ path: '', content: iterableOf(content) }))
+        await testContent(iterableOf({ path: '', content: iterableOf(content()) }))
       })
 
       it(`Iterable<{ path: '', content: AsyncIterable<${name}> }>`, async function () {
-        await testContent(iterableOf({ path: '', content: asyncIterableOf(content) }))
+        await testContent(iterableOf({ path: '', content: asyncIterableOf(content()) }))
       })
 
       it(`AsyncIterable<{ path: '', content: Iterable<${name}> }>`, async function () {
-        await testContent(asyncIterableOf({ path: '', content: iterableOf(content) }))
+        await testContent(asyncIterableOf({ path: '', content: iterableOf(content()) }))
       })
 
       it(`AsyncIterable<{ path: '', content: AsyncIterable<${name}> }>`, async function () {
-        await testContent(asyncIterableOf({ path: '', content: asyncIterableOf(content) }))
+        await testContent(asyncIterableOf({ path: '', content: asyncIterableOf(content()) }))
       })
     }
   }
@@ -124,6 +132,14 @@ describe('normalise-input', function () {
     testInputType(BLOB, 'Blob', false)
   })
 
+  describe('window.ReadableStream', () => {
+    if (!supportsFileReader) {
+      return
+    }
+
+    testInputType(WINDOW_READABLE_STREAM, 'window.ReadableStream', false)
+  })
+
   describe('Iterable<Number>', () => {
     testInputType(ARRAY, 'Iterable<Number>', false)
   })