fix(generateSendOpReturnWeb): Restoring old SLP Send for web

src/slp/tokentype1.js

@@ -2,6 +2,7 @@
 //const bchjs = new BCHJS()
 
 const Address = require("./address")
+const Script = require("../script")
 
 const BigNumber = require("bignumber.js")
 const slpMdm = require("slp-mdm")
@@ -15,6 +16,7 @@ class TokenType1 {
     this.restURL = config.restURL
 
     addy = new Address(config)
+    this.Script = new Script()
 
     // Instantiate the transaction builder.
     TransactionBuilder.setAddress(addy)
@@ -123,6 +125,90 @@ class TokenType1 {
     }
   }
 
+  /**
+   * @api SLP.TokenType1.generateSendOpReturnWeb() generateSendOpReturnWeb() - Web-friendly OP_RETURN code for SLP Send tx
+   * @apiName generateSendOpReturnWeb
+   * @apiGroup SLP
+   * @apiDescription Generate the OP_RETURN value needed to create an SLP Send transaction.
+   * It's assumed all elements in the tokenUtxos array belong to the same token.
+   * Returns an object with two properties:
+   *  - script: an array of Bufers that is ready to fed into bchjs.Script.encode2() to be turned into a transaction output.
+   *  - outputs: an integer with a value of 1 or 2. If 2, indicates there needs to be an extra output to send token change.
+   */
+  generateSendOpReturnWeb(tokenUtxos, sendQty) {
+    try {
+      const tokenId = tokenUtxos[0].tokenId
+      const decimals = tokenUtxos[0].decimals
+
+      // Calculate the total amount of tokens owned by the wallet.
+      let totalTokens = 0
+      for (let i = 0; i < tokenUtxos.length; i++)
+        totalTokens += tokenUtxos[i].tokenQty
+
+      const change = totalTokens - sendQty
+      // console.log(`change: ${change}`)
+
+      let script
+      let outputs = 1
+
+      // The normal case, when there is token change to return to sender.
+      if (change > 0) {
+        outputs = 2
+
+        let baseQty = new BigNumber(sendQty).times(10 ** decimals)
+        baseQty = baseQty.absoluteValue()
+        baseQty = Math.floor(baseQty)
+        let baseQtyHex = baseQty.toString(16)
+        baseQtyHex = baseQtyHex.padStart(16, "0")
+
+        let baseChange = new BigNumber(change).times(10 ** decimals)
+        baseChange = baseChange.absoluteValue()
+        baseChange = Math.floor(baseChange)
+        // console.log(`baseChange: ${baseChange.toString()}`)
+
+        let baseChangeHex = baseChange.toString(16)
+        baseChangeHex = baseChangeHex.padStart(16, "0")
+        // console.log(`baseChangeHex padded: ${baseChangeHex}`)
+
+        script = [
+          this.Script.opcodes.OP_RETURN,
+          Buffer.from("534c5000", "hex"),
+          //BITBOX.Script.opcodes.OP_1,
+          Buffer.from("01", "hex"),
+          Buffer.from(`SEND`),
+          Buffer.from(tokenId, "hex"),
+          Buffer.from(baseQtyHex, "hex"),
+          Buffer.from(baseChangeHex, "hex")
+        ]
+      } else {
+        // Corner case, when there is no token change to send back.
+
+        let baseQty = new BigNumber(sendQty).times(10 ** decimals)
+        baseQty = baseQty.absoluteValue()
+        baseQty = Math.floor(baseQty)
+        let baseQtyHex = baseQty.toString(16)
+        baseQtyHex = baseQtyHex.padStart(16, "0")
+
+        // console.log(`baseQty: ${baseQty.toString()}`)
+
+        script = [
+          this.Script.opcodes.OP_RETURN,
+          Buffer.from("534c5000", "hex"),
+          //BITBOX.Script.opcodes.OP_1,
+          Buffer.from("01", "hex"),
+          Buffer.from(`SEND`),
+          Buffer.from(tokenId, "hex"),
+          Buffer.from(baseQtyHex, "hex")
+        ]
+      }
+
+      return { script, outputs }
+    } catch (err) {
+      console.log(`Error in generateSendOpReturnWeb()`)
+      throw err
+    }
+  }
+
   /**
    * @api SLP.TokenType1.generateBurnOpReturn() generateBurnOpReturn()
    * @apiName generateBurnOpReturn

test/unit/slp-tokentype1.js

@@ -70,6 +70,125 @@ describe("#SLP TokenType1", () => {
     })
   })
 
+  describe("#generateSendOpReturnWeb", () => {
+    it("should generate send OP_RETURN code", async () => {
+      // Mock UTXO.
+      const tokenUtxos = [
+        {
+          txid:
+            "a8eb788b8ddda6faea00e6e2756624b8feb97655363d0400dd66839ea619d36e",
+          vout: 2,
+          value: "546",
+          confirmations: 0,
+          satoshis: 546,
+          utxoType: "token",
+          transactionType: "send",
+          tokenId:
+            "497291b8a1dfe69c8daea50677a3d31a5ef0e9484d8bebb610dac64bbc202fb7",
+          tokenTicker: "TOK-CH",
+          tokenName: "TokyoCash",
+          tokenDocumentUrl: "",
+          tokenDocumentHash: "",
+          decimals: 8,
+          tokenQty: 7
+        }
+      ]
+
+      const result = await bchjs.SLP.TokenType1.generateSendOpReturnWeb(
+        tokenUtxos,
+        1
+      )
+      // console.log(`result: ${JSON.stringify(result, null, 2)}`)
+
+      assert.hasAllKeys(result, ["script", "outputs"])
+      assert.isNumber(result.outputs)
+    })
+
+    it("should handle problematic configuration", async () => {
+      // Mock UTXO.
+      const tokenUtxos = [
+        {
+          txid:
+            "0bd6b874246202b4cbc2f501419a5ce6f9b01e8ba9521298afd15c7e8eac5951",
+          vout: 2,
+          value: "546",
+          confirmations: 0,
+          satoshis: 546,
+          utxoType: "token",
+          transactionType: "send",
+          tokenId:
+            "155784a206873c98acc09e8dabcccf6abf13c4c14d8662190534138a16bb93ce",
+          tokenTicker: "PSF",
+          tokenName: "PSF Testnet Token",
+          tokenDocumentUrl: "",
+          tokenDocumentHash: "",
+          decimals: 8,
+          tokenQty: 18004.71169917
+        }
+      ]
+
+      const result = await bchjs.SLP.TokenType1.generateSendOpReturnWeb(
+        tokenUtxos,
+        5000
+      )
+      // console.log(`result: ${JSON.stringify(result, null, 2)}`)
+      // console.log(`result.script: `, result.script)
+      // console.log(`result.script: `, result.script.toString("hex"))
+
+      // This transaction failed due to a floating point error. This is expressed
+      // by the script[6] being length 2 (incorrect) instead of 8 (correct).
+      assert.equal(result.script[5].length, 8)
+      assert.equal(result.script[6].length, 8)
+    })
+
+    it("should generate good OP_RETURN for problematic TX", () => {
+      const utxo1 = {
+        txid:
+          "35287aa2aa7d3f1954fbbcb8a748d8773359b4f2771a851959a4a6116bcb552c",
+        vout: 1,
+        amount: 0.00000546,
+        satoshis: 546,
+        legacyAddress: "1MuLZ9LzLSTKioBHoPzeSfFANTEN2CZhuS",
+        cashAddress: "bitcoincash:qrj5sala6z53v559q54mekexru2xe34yrquhmpy5kx",
+        tokenId:
+          "c4b0d62156b3fa5c8f3436079b5394f7edc1bef5dc1cd2f9d0c4d46f82cca479",
+        decimals: 2,
+        tokenQty: 1371.6
+      }
+
+      const utxo2 = {
+        txid:
+          "cb652ce62babc81936f0f1e1d5b80102cb44de99dece83f4bbd34cfaeef744b0",
+        vout: 2,
+        amount: 0.00000546,
+        satoshis: 546,
+        legacyAddress: "1LzjkvDVB16k6kcSz8hZodW9KPP2zxwmGh",
+        cashAddress: "bitcoincash:qrd4tj48lpf0wv36qt5mkd6c3n4h5xcfgqqw77s63d",
+        tokenId:
+          "c4b0d62156b3fa5c8f3436079b5394f7edc1bef5dc1cd2f9d0c4d46f82cca479",
+        decimals: 2,
+        tokenQty: 3250.75
+      }
+
+      const utxos = [utxo1, utxo2]
+
+      const { script } = bchjs.SLP.TokenType1.generateSendOpReturnWeb(
+        utxos,
+        1400
+      )
+
+      // console.log(`script: `, script)
+      // console.log(`outputs: `, outputs)
+
+      // console.log(`script[6]: ${script[6].toString("hex")}`)
+      // console.log(`script[6].length: ${script[6].length}`)
+
+      // This transaction failed due to a floating point error. This is expressed
+      // by the script[6] being length 2 (incorrect) instead of 8 (correct).
+      assert.equal(script[6].length, 8)
+    })
+  })
+
   describe("#generateBurnOpReturn", () => {
     it("should generate burn OP_RETURN code", () => {
       // Mock UTXO.