deno.land / std@0.224.0 / json / json_parse_stream.ts

json_parse_stream.ts
View Documentation
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
65
66
67
68
69
70
71
72
73
74
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
import type { JsonValue, ParseStreamOptions } from "./common.ts";import { parse } from "./_common.ts";
const branks = /^[ \t\r\n]*$/;function isBrankString(str: string) { return branks.test(str);}
/** * Parse each chunk as JSON. * * This can be used to parse {@link https://jsonlines.org/ | JSON lines}, {@link http://ndjson.org/ | NDJSON} and {@link https://datatracker.ietf.org/doc/html/rfc7464 | JSON Text Sequences}. * Chunks consisting of spaces, tab characters, or newline characters will be ignored. * * @example * parse JSON lines or NDJSON * ```ts * import { TextLineStream } from "https://deno.land/std@$STD_VERSION/streams/text_line_stream.ts"; * import { JsonParseStream } from "https://deno.land/std@$STD_VERSION/json/json_parse_stream.ts"; * * const url = "https://deno.land/std@$STD_VERSION/json/testdata/test.jsonl"; * const { body } = await fetch(url); * * const readable = body! * .pipeThrough(new TextDecoderStream()) // convert Uint8Array to string * .pipeThrough(new TextLineStream()) // transform into a stream where each chunk is divided by a newline * .pipeThrough(new JsonParseStream()); // parse each chunk as JSON * * for await (const data of readable) { * console.log(data); * } * ``` * * @example * parse JSON Text Sequences * ```ts * import { TextDelimiterStream } from "https://deno.land/std@$STD_VERSION/streams/text_delimiter_stream.ts"; * import { JsonParseStream } from "https://deno.land/std@$STD_VERSION/json/json_parse_stream.ts"; * * const url = * "https://deno.land/std@$STD_VERSION/json/testdata/test.json-seq"; * const { body } = await fetch(url); * * const delimiter = "\x1E"; * const readable = body! * .pipeThrough(new TextDecoderStream()) * .pipeThrough(new TextDelimiterStream(delimiter)) // transform into a stream where each chunk is divided by a delimiter * .pipeThrough(new JsonParseStream()); * * for await (const data of readable) { * console.log(data); * } * ``` */export class JsonParseStream extends TransformStream<string, JsonValue> { /** Constructs new instance. */ constructor({ writableStrategy, readableStrategy }: ParseStreamOptions = {}) { super( { transform(chunk, controller) { if (!isBrankString(chunk)) { controller.enqueue(parse(chunk)); } }, }, writableStrategy, readableStrategy, ); }}
std

Version Info

Tagged at
6 months ago