37 lines
903 B
JavaScript
37 lines
903 B
JavaScript
const cache = new Map()
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const expiresIn = 1000 * 30 // 30 seconds in milliseconds
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async function fetchChainFeeRate () {
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const url = 'https://mempool.space/api/v1/fees/recommended'
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const chainFee = await fetch(url)
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.then((res) => res.json())
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.then((body) => body.hourFee)
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.catch((err) => {
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console.error('fetchChainFee', err)
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return 0
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})
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cache.set('fee', { fee: chainFee, createdAt: Date.now() })
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return chainFee
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}
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async function getChainFeeRate () {
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if (cache.has('fee')) {
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const { fee, createdAt } = cache.get('fee')
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const expired = createdAt + expiresIn < Date.now()
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if (expired) fetchChainFeeRate().catch(console.error) // update cache
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return fee
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} else {
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fetchChainFeeRate().catch(console.error)
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}
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return 0
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}
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export default {
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Query: {
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chainFee: async (parent, opts, ctx) => {
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return await getChainFeeRate()
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}
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}
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}
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