Add Electrumx Broadcast TX method

src/electrumx.js

@@ -543,6 +543,46 @@ class ElectrumX {
       else throw error
     }
   }
+
+  /**
+   * @api Electrumx.broadcast()  broadcast()
+   * @apiName ElectrumX Broadcast
+   * @apiGroup ElectrumX
+   * @apiDescription Broadcast a raw transaction and return the transaction ID on success or error on failure.
+   *
+   *    (async () => {
+   *   try {
+   *     const txHex = "020000000265d13ef402840c8a51f39779afb7ae4d49e4b0a3c24a3d0e7742038f2c679667010000006441dd1dd72770cadede1a7fd0363574846c48468a398ddfa41a9677c74cac8d2652b682743725a3b08c6c2021a629011e11a264d9036e9d5311e35b5f4937ca7b4e4121020797d8fd4d2fa6fd7cdeabe2526bfea2b90525d6e8ad506ec4ee3c53885aa309ffffffff65d13ef402840c8a51f39779afb7ae4d49e4b0a3c24a3d0e7742038f2c679667000000006441347d7f218c11c04487c1ad8baac28928fb10e5054cd4494b94d078cfa04ccf68e064fb188127ff656c0b98e9ce87f036d183925d0d0860605877d61e90375f774121028a53f95eb631b460854fc836b2e5d31cad16364b4dc3d970babfbdcc3f2e4954ffffffff035ac355000000000017a914189ce02e332548f4804bac65cba68202c9dbf822878dfd0800000000001976a914285bb350881b21ac89724c6fb6dc914d096cd53b88acf9ef3100000000001976a91445f1f1c4a9b9419a5088a3e9c24a293d7a150e6488ac00000000"
+   *     let result = await bchjs.Electrumx.broadcast(txHex)
+   *     console.log(result);
+   *   } catch(error) {
+   *    console.error(error)
+   *   }
+   * })()
+   *
+   * result = {
+   *  "success": true,
+   *  "txid": "..."
+   * }
+  */
+  async broadcast(txHex) {
+    try {
+      if (typeof txHex === "string") {
+        const response = await axios.post(
+          `${this.restURL}electrumx/tx/broadcast`,
+          { txHex },
+          _this.axiosOptions
+        )
+
+        return response.data
+      }
+
+      throw new Error(`Input txHex must be a string.`)
+    } catch (error) {
+      if (error.response && error.response.data) throw error.response.data
+      else throw error
+    }
+  }
 }
 
 module.exports = ElectrumX