feat(Utxo.isValid()): can test if a UTXO has been spent

Author: christroutner

src/utxo.js

@@ -10,6 +10,7 @@ const Electrumx = require('./electrumx')
 const Slp = require('./slp/slp')
 const PsfSlpIndexer = require('./psf-slp-indexer')
 const BigNumber = require('bignumber.js')
+const Blockchain = require('./blockchain')
 
 class UTXO {
   constructor (config = {}) {
@@ -18,6 +19,7 @@ class UTXO {
     this.slp = new Slp(config)
     this.psfSlpIndexer = new PsfSlpIndexer(config)
     this.BigNumber = BigNumber
+    this.blockchain = new Blockchain(config)
   }
 
   /**
@@ -207,7 +209,7 @@ class UTXO {
 
       return outObj
     } catch (err) {
-      console.error('Error in bchjs.Utxo.get(): ', err)
+      console.error('Error in bchjs.Utxo.get()')
 
       if (err.error) throw new Error(err.error)
       throw err
@@ -336,6 +338,57 @@ class UTXO {
 
     return utxos[largestIndex]
   }
+
+  /**
+   * @api Utxo.isValid() isValid()
+   * @apiName isValid
+   * @apiGroup UTXO
+   * @apiDescription Validate that UTXO exists and is still spendable.
+   *
+   * Given a UTXO, this method will return true if the UTXO is still in the
+   * mempool and still valid for spending. It will return false if the UTXO
+   * has been spent.
+   *
+   * @apiExample Example usage:
+   * (async () => {
+   *   try {
+   *     const utxos = await bchjs.Utxo.get('bitcoincash:qq54fgjn3hz0357n8a6guy4demw9xfkjk5jcj0xr0z');
+   *     const isValid = bchjs.Utxo.isValid(utxos.bchUtxos[0])
+   *     console.log(isValid);
+   *   } catch(error) {
+   *    console.error(error)
+   *   }
+   * })()
+   *
+   * // returns
+   *  true
+   */
+  async isValid (utxo) {
+    try {
+      // console.log('utxo: ', utxo)
+
+      // Convert different properties from different indexers
+      const txid = utxo.txid || utxo.tx_hash
+      const vout = utxo.vout | utxo.tx_pos
+
+      // Query the full node
+      const txOut = await this.blockchain.getTxOut(txid, vout, true)
+      // console.log('txOut: ', txOut)
+
+      // Simplify results to either true or false.
+      let isValid = null
+      if (txOut === null) {
+        isValid = false
+      } else {
+        isValid = true
+      }
+
+      return isValid
+    } catch (err) {
+      console.log('Error in Utxo.isValid()')
+      throw err
+    }
+  }
 }
 
 module.exports = UTXO

test/integration/chains/bchn/utxo-integration.js

@@ -122,6 +122,65 @@ describe('#UTXO', () => {
       assert.isAbove(result.slpUtxos.nft.tokens.length, 0)
     })
   })
+
+  describe('#isValid', () => {
+    it('should return true for valid UTXO with fullnode properties', async () => {
+      const utxo = {
+        txid: 'b94e1ff82eb5781f98296f0af2488ff06202f12ee92b0175963b8dba688d1b40',
+        vout: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result)
+
+      assert.equal(result, true)
+    })
+
+    it('should return true for valid UTXO with fulcrum properties', async () => {
+      const utxo = {
+        tx_hash: 'b94e1ff82eb5781f98296f0af2488ff06202f12ee92b0175963b8dba688d1b40',
+        tx_pos: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result)
+
+      assert.equal(result, true)
+    })
+
+    it('should return true for valid UTXO with fullnode properties', async () => {
+      const utxo = {
+        txid: '17754221b29f189532d4fc2ae89fb467ad2dede30fdec4854eb2129b3ba90d7a',
+        vout: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result)
+
+      assert.equal(result, false)
+    })
+
+    it('should return true for valid UTXO with fulcrum properties', async () => {
+      const utxo = {
+        tx_hash: '17754221b29f189532d4fc2ae89fb467ad2dede30fdec4854eb2129b3ba90d7a',
+        tx_pos: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result
+
+      assert.equal(result, false)
+    })
+
+    it('should process output of Utxo.get()', async () => {
+      const utxo = await bchjs.Utxo.get('bitcoincash:qr4yscpw9jgq8ltajfeknpj32kamkf9knujffcdhyq')
+      // console.log(`utxo: ${JSON.stringify(utxo, null, 2)}`)
+
+      const result = await bchjs.Utxo.isValid(utxo.bchUtxos[0])
+
+      assert.equal(result, true)
+    })
+  })
 })
 
 function sleep (ms) {

test/unit/utxo-unit.js

@@ -174,4 +174,36 @@ describe('#utxo', () => {
       assert.equal(result.nullUtxos.length, 0)
     })
   })
+
+  describe('#isValid', () => {
+    it('should return false if getTxOut() returns null', async () => {
+      // Mock dependencies
+      sandbox.stub(bchjs.Utxo.blockchain, 'getTxOut').resolves(null)
+
+      const utxo = {
+        tx_hash: '17754221b29f189532d4fc2ae89fb467ad2dede30fdec4854eb2129b3ba90d7a',
+        tx_pos: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result
+
+      assert.equal(result, false)
+    })
+
+    it('should return true if getTxOut() returns non-null output', async () => {
+      // Mock dependencies
+      sandbox.stub(bchjs.Utxo.blockchain, 'getTxOut').resolves({ a: 'b' })
+
+      const utxo = {
+        tx_hash: 'b94e1ff82eb5781f98296f0af2488ff06202f12ee92b0175963b8dba688d1b40',
+        tx_pos: 0
+      }
+
+      const result = await bchjs.Utxo.isValid(utxo)
+      // console.log('result: ', result
+
+      assert.equal(result, true)
+    })
+  })
 })