feat(read-chunk): add readChunkStrict

@vates/read-chunk/.USAGE.md

@@ -1,3 +1,5 @@
+### `readChunk(stream, [size])`
+
 - returns the next available chunk of data
 - like `stream.read()`, a number of bytes can be specified
 - returns with less data than expected if stream has ended
@@ -12,3 +14,13 @@ import { readChunk } from '@vates/read-chunk'
   }
 })()
 ```
+
+### `readChunkStrict(stream, [size])`
+
+Similar behavior to `readChunk` but throws if the stream ended before the requested data could be read.
+
+```js
+import { readChunkStrict } from '@vates/read-chunk'
+
+const chunk = await readChunkStrict(stream, 1024)
+```

@vates/read-chunk/README.md

@@ -16,6 +16,8 @@ Installation of the [npm package](https://npmjs.org/package/@vates/read-chunk):
 
 ## Usage
 
+### `readChunk(stream, [size])`
+
 - returns the next available chunk of data
 - like `stream.read()`, a number of bytes can be specified
 - returns with less data than expected if stream has ended
@@ -31,6 +33,16 @@ import { readChunk } from '@vates/read-chunk'
 })()
 ```
 
+### `readChunkStrict(stream, [size])`
+
+Similar behavior to `readChunk` but throws if the stream ended before the requested data could be read.
+
+```js
+import { readChunkStrict } from '@vates/read-chunk'
+
+const chunk = await readChunkStrict(stream, 1024)
+```
+
 ## Contributions
 
 Contributions are _very_ welcomed, either on the documentation or on

@vates/read-chunk/index.js

@@ -30,3 +30,22 @@ const readChunk = (stream, size) =>
         onReadable()
       })
 exports.readChunk = readChunk
+
+exports.readChunkStrict = async function readChunkStrict(stream, size) {
+  const chunk = await readChunk(stream, size)
+  if (chunk === null) {
+    throw new Error('stream has ended without data')
+  }
+
+  if (size !== undefined && chunk.length !== size) {
+    const error = new Error('stream has ended with not enough data')
+    Object.defineProperties(error, {
+      chunk: {
+        value: chunk,
+      },
+    })
+    throw error
+  }
+
+  return chunk
+}

@vates/read-chunk/index.spec.js

@@ -4,7 +4,7 @@
 
 const { Readable } = require('stream')
 
-const { readChunk } = require('./')
+const { readChunk, readChunkStrict } = require('./')
 
 const makeStream = it => Readable.from(it, { objectMode: false })
 makeStream.obj = Readable.from
@@ -43,3 +43,27 @@ describe('readChunk', () => {
     })
   })
 })
+
+const rejectionOf = promise =>
+  promise.then(
+    value => {
+      throw value
+    },
+    error => error
+  )
+
+describe('readChunkStrict', function () {
+  it('throws if stream is empty', async () => {
+    const error = await rejectionOf(readChunkStrict(makeStream([])))
+    expect(error).toBeInstanceOf(Error)
+    expect(error.message).toBe('stream has ended without data')
+    expect(error.chunk).toEqual(undefined)
+  })
+
+  it('throws if stream ends with not enough data', async () => {
+    const error = await rejectionOf(readChunkStrict(makeStream(['foo', 'bar']), 10))
+    expect(error).toBeInstanceOf(Error)
+    expect(error.message).toBe('stream has ended with not enough data')
+    expect(error.chunk).toEqual(Buffer.from('foobar'))
+  })
+})

CHANGELOG.unreleased.md

@@ -29,6 +29,7 @@
 
 <!--packages-start-->
 
+- @vates/read-chunk major
 - xo-server patch
 
 <!--packages-end-->