-
Notifications
You must be signed in to change notification settings - Fork 0
/
utils.ts
64 lines (57 loc) · 1.44 KB
/
utils.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
/**
* Iterates over a ReadableStream, yielding chunks of data.
*
* ```ts
* const response = await fetch("https://example.com");
* for await (const chunk of iterateStream(response.body)) {
* console.log(chunk);
* }
* ```
*/
export async function* iterateStream(stream: ReadableStream, options?: {
bufSize?: number;
}) {
const reader = stream.getReader();
const bufSize = options?.bufSize ?? 65_536;
const emptyArray = new Uint8Array(0);
let buffer = emptyArray;
while (true) {
const { value, done } = await reader.read();
if (done) {
// Yield the last chunk.
if (buffer.byteLength > 0) {
yield buffer;
}
break;
}
// Constructs a new buffer to hold all the data so far.
const chunk = new Uint8Array(buffer.byteLength + value.byteLength);
chunk.set(buffer, 0);
chunk.set(value, buffer.byteLength);
if (chunk.byteLength >= bufSize) {
yield chunk;
// Reset the buffer.
buffer = emptyArray;
} else {
buffer = chunk;
}
}
}
/**
* Displays progress of a ReadableStream.
*/
export class Progress extends TransformStream {
constructor(onProgress?: (progress: number) => void) {
let completed = 0;
super({
transform: (
chunk: Uint8Array,
controller: TransformStreamDefaultController,
) => {
completed += chunk.byteLength;
onProgress?.(completed);
controller.enqueue(chunk);
},
});
}
}