phemex.js

import Exchange from '../services/exchange'

class Phemex extends Exchange {
  constructor(options) {
    super(options)

    this.id = 'phemex'
    this.wsid = 99887766

    this.endpoints = {
      PRODUCTS: 'https://api.phemex.com/exchange/public/cfg/v2/products'
    }

    this.matchPairName = pair => {
      let id = this.products[pair]

      if (!id) {
        for (let name in this.products) {
          if (pair === this.products[name]) {
            id = this.products[name]
            break
          }
        }
      }
      return id || false
    }

    this.options = Object.assign(
      {
        url: () => {
          return `wss://phemex.com/ws`
        }
      },
      this.options
    )

    this.initialize()
  }

  connect() {
    const validation = super.connect()
    if (!validation) return Promise.reject()
    else if (validation instanceof Promise) return validation

    return new Promise((resolve, reject) => {
      this.api = new WebSocket(this.getUrl())

      this.api.onmessage = event => {
        this.queueTrades(this.formatLiveTrades(JSON.parse(event.data)))
      }

      this.api.onopen = e => {
        this.api.send(
          JSON.stringify({
            id: this.wsid,
            method: 'trade.subscribe',
            params: this.pairs
          })
        )
        this.keepalive = setInterval(() => {
          this.api.send(
            JSON.stringify({
              id: this.wsid,
              method: 'server.ping',
              params: []
            })
          )
        }, 21000)

        this.emitOpen(e)

        resolve()
      }

      this.api.onclose = event => {
        this.emitClose(event)
        clearInterval(this.keepalive)
      }
      this.api.onerror = () => {
        this.emitError({ message: `${this.id} disconnected` })
        reject()
      }
    })
  }

  disconnect() {
    if (!super.disconnect()) return

    if (this.api && this.api.readyState < 2) {
      this.api.close()
    }
  }

  formatLiveTrades(json) {
    if (!json || !json.trades || !json.trades.length) {
      return
    }

    return json.trades.map(trade => {
      const output = {
        exchange: this.id,
        timestamp: +new Date(),
        price: +trade[2] / 10000,
        size: +trade[3] / (+trade[2] / 10000),
        side: trade[1].toLowerCase()
      }

      return output
    })
  }

  formatProducts(response) {
    return response.data.products.map(a => a.symbol)
  }
}

export default Phemex