|
1
|
2 |
|
import { BackendError, FetchError, MalformedError } from './errors' |
|
2
|
|
|
|
|
3
|
|
|
export type CurrencyCode = string; |
|
4
|
|
|
|
|
5
|
|
|
interface YFResponse { |
|
6
|
|
|
chart: { |
|
7
|
|
|
result: { |
|
8
|
|
|
meta: { |
|
9
|
|
|
regularMarketPrice: number |
|
10
|
|
|
} |
|
11
|
|
|
}[] |
|
12
|
|
|
} |
|
13
|
|
|
} |
|
14
|
|
|
|
|
15
|
|
|
interface CachedRate { |
|
16
|
|
|
value: number; |
|
17
|
|
|
timestamp: number; |
|
18
|
|
|
} |
|
19
|
|
|
|
|
20
|
|
|
interface ExchangeRateOptions { |
|
21
|
|
|
cacheDurationMs?: number; // Defaults to undefined (no caching) |
|
22
|
|
|
} |
|
23
|
|
|
|
|
24
|
2 |
|
const YF_BASE = 'https://query1.finance.yahoo.com/v8/finance/chart/' |
|
25
|
2 |
|
const YF_PARAMS = '=X?region=US&lang=en-US&includePrePost=false&interval=2m&useYfid=true&range=1d&corsDomain=finance.yahoo.com&.tsrc=finance' |
|
26
|
|
|
|
|
27
|
2 |
|
const rateCache: Record<string, CachedRate> = {} |
|
28
|
|
|
|
|
29
|
|
|
function getRateUrl (from: CurrencyCode, to: CurrencyCode): string { |
|
30
|
13 |
|
return `${YF_BASE}${from.toUpperCase()}${to.toUpperCase()}${YF_PARAMS}` |
|
31
|
|
|
} |
|
32
|
|
|
|
|
33
|
|
|
function isCacheValid (cachedRate: CachedRate, cacheDurationMs: number): boolean { |
|
34
|
3 |
|
return Date.now() - cachedRate.timestamp < cacheDurationMs |
|
35
|
|
|
} |
|
36
|
|
|
|
|
37
|
|
|
function getCachedRate (from: CurrencyCode, to: CurrencyCode, cacheDurationMs?: number): number | null { |
|
38
|
14 |
|
const cacheKey = `${from}-${to}` |
|
39
|
14 |
|
const cachedRate = rateCache[cacheKey] |
|
40
|
14 |
|
return (cacheDurationMs && cachedRate && isCacheValid(cachedRate, cacheDurationMs)) ? cachedRate.value : null |
|
41
|
|
|
} |
|
42
|
|
|
|
|
43
|
|
|
async function fetchResponse (rateUrl: string): Promise<Response> { |
|
44
|
13 |
|
const response = await fetch(rateUrl) |
|
45
|
12 |
|
if (!response.ok) { |
|
46
|
2 |
|
throw new BackendError(`Service did not return HTTP 200 response. Status: ${response.status}`) |
|
47
|
|
|
} |
|
48
|
10 |
|
return response |
|
49
|
|
|
} |
|
50
|
|
|
|
|
51
|
|
|
function parseRateFromResponse (result: YFResponse): number { |
|
52
|
10 |
|
const rate = result.chart?.result[0]?.meta?.regularMarketPrice |
|
53
|
10 |
|
if (!rate) { |
|
54
|
1 |
|
throw new MalformedError('Unexpected response structure. Missing "regularMarketPrice".') |
|
55
|
|
|
} |
|
56
|
9 |
|
return rate |
|
57
|
|
|
} |
|
58
|
|
|
|
|
59
|
|
|
async function fetchRate (rateUrl: string): Promise<number> { |
|
60
|
13 |
|
try { |
|
61
|
13 |
|
const response = await fetchResponse(rateUrl) |
|
62
|
10 |
|
const responseData: YFResponse = await response.json() |
|
63
|
10 |
|
return parseRateFromResponse(responseData) |
|
64
|
|
|
} catch (error) { |
|
65
|
4 |
|
if (error instanceof BackendError || error instanceof MalformedError) { |
|
66
|
3 |
|
throw error |
|
67
|
|
|
} |
|
68
|
1 |
|
throw new FetchError(`Failed to fetch data from ${rateUrl}`) |
|
69
|
|
|
} |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
2 |
|
export async function getExchangeRate ( |
|
73
|
|
|
from: CurrencyCode, |
|
74
|
|
|
to: CurrencyCode, |
|
75
|
|
|
options: ExchangeRateOptions = {} |
|
76
|
|
|
): Promise<number> { |
|
77
|
14 |
|
const cachedRate = getCachedRate(from, to, options.cacheDurationMs) |
|
78
|
14 |
|
if (cachedRate !== null) { |
|
79
|
1 |
|
return cachedRate |
|
80
|
|
|
} |
|
81
|
|
|
|
|
82
|
13 |
|
const rateUrl = getRateUrl(from, to) |
|
83
|
13 |
|
const rate = await fetchRate(rateUrl) |
|
84
|
|
|
|
|
85
|
9 |
|
if (options.cacheDurationMs) { |
|
86
|
3 |
|
const cacheKey = `${from}-${to}` |
|
87
|
3 |
|
rateCache[cacheKey] = { value: rate, timestamp: Date.now() } // Cache the result with a timestamp |
|
88
|
|
|
} |
|
89
|
|
|
|
|
90
|
9 |
|
return rate |
|
91
|
|
|
} |
|
92
|
|
|
|
|
93
|
|
|
|
|
94
|
|
|
export * from './errors' |
|
95
|
|
|
|
tamtamchik /
exchanger
