Make the default usage check the price status (#11)

* Check the status of the price

* fix lint errors

* drive-by: bump solana web3 version

* bump minor version

Co-authored-by: Jayant Krishnamurthy <[email protected]>

Author: jayantk

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@pythnetwork/client",
-  "version": "2.3.2",
+  "version": "2.4.0",
   "description": "Client for consuming Pyth price data",
   "homepage": "https://pyth.network",
   "main": "lib/index.js",
@@ -37,7 +37,7 @@
     "typescript": "^4.2.4"
   },
   "dependencies": {
-    "@solana/web3.js": "^1.10.1",
+    "@solana/web3.js": "^1.30.2",
     "assert": "^2.0.0",
     "buffer": "^6.0.1"
   }

package.json

@@ -10,8 +10,13 @@ const pythConnection = new PythConnection(connection, pythPublicKey)
 pythConnection.onPriceChange((product, price) => {
   // sample output:
   // SRM/USD: $8.68725 ±$0.0131
-  // tslint:disable-next-line:no-console
-  console.log(`${product.symbol}: $${price.price} \xB1$${price.confidence}`)
+  if (price.price && price.confidence) {
+    // tslint:disable-next-line:no-console
+    console.log(`${product.symbol}: $${price.price} \xB1$${price.confidence}`)
+  } else {
+    // tslint:disable-next-line:no-console
+    console.log(`${product.symbol}: price currently unavailable`)
+  }
 })
 
 // tslint:disable-next-line:no-console

src/example_usage.ts

@@ -67,7 +67,7 @@ export interface Ema {
   denominator: bigint
 }
 
-export interface PriceData extends Base, Price {
+export interface PriceData extends Base {
   priceType: number
   exponent: number
   numComponentPrices: number
@@ -90,6 +90,15 @@ export interface PriceData extends Base, Price {
   drv3Component: bigint
   drv3: number
   priceComponents: PriceComponent[]
+  aggregate: Price,
+  // The current price and confidence. The typical use of this interface is to consume these two fields.
+  // If undefined, Pyth does not currently have price information for this product. This condition can
+  // happen for various reasons (e.g., US equity market is closed, or insufficient publishers), and your
+  // application should handle it gracefully. Note that other raw price information fields (such as
+  // aggregate.price) may be defined even if this is undefined; you most likely should not use those fields,
+  // as their value can be arbitrary when this is undefined.
+  price: number | undefined
+  confidence: number | undefined,
 }
 
 /** Parse data as a generic Pyth account. Use this method if you don't know the account type. */
@@ -257,7 +266,15 @@ export const parsePriceData = (data: Buffer): PriceData => {
   // space for future derived values
   const drv3Component = readBigInt64LE(data, 200)
   const drv3 = Number(drv3Component) * 10 ** exponent
-  const aggregatePriceInfo = parsePriceInfo(data.slice(208, 240), exponent)
+  const aggregate = parsePriceInfo(data.slice(208, 240), exponent)
+
+  let price
+  let confidence
+  if (aggregate.status === 1) {
+    price = aggregate.price
+    confidence = aggregate.confidence
+  }
+
   // price components - up to 32
   const priceComponents: PriceComponent[] = []
   let offset = 240
@@ -266,15 +283,16 @@ export const parsePriceData = (data: Buffer): PriceData => {
     const publisher = PKorNull(data.slice(offset, offset + 32))
     offset += 32
     if (publisher) {
-      const aggregate = parsePriceInfo(data.slice(offset, offset + 32), exponent)
+      const componentAggregate = parsePriceInfo(data.slice(offset, offset + 32), exponent)
       offset += 32
       const latest = parsePriceInfo(data.slice(offset, offset + 32), exponent)
       offset += 32
-      priceComponents.push({ publisher, aggregate, latest })
+      priceComponents.push({ publisher, aggregate: componentAggregate, latest })
     } else {
       shouldContinue = false
     }
   }
+
   return {
     magic,
     version,
@@ -301,8 +319,10 @@ export const parsePriceData = (data: Buffer): PriceData => {
     previousConfidence,
     drv3Component,
     drv3,
-    ...aggregatePriceInfo,
+    aggregate,
     priceComponents,
+    price,
+    confidence
   }
 }