use a better code comparison

libs/remix-lib/src/util.ts

@@ -1,5 +1,6 @@
 'use strict'
 import { BN, bufferToHex, keccak, setLengthLeft, toBuffer, addHexPrefix } from 'ethereumjs-util'
+import stringSimilarity from 'string-similarity'
 
 /*
  contains misc util: @TODO should be splitted
@@ -222,8 +223,9 @@ export function compareByteCode (code1, code2) {
   code2 = this.extractSwarmHash(code2)
   code2 = this.extractcborMetadata(code2)
 
-  if (code1 && code2 && code1.indexOf(code2) === 0) {
+  if (code1 && code2) {
-    return true
+    const compare = stringSimilarity.compareTwoStrings(code1, code2)
+    return compare > 0.5
   }
   return false
 }

package-lock.json

@@ -36072,6 +36072,11 @@
         }
       }
     },
+    "string-similarity": {
+      "version": "4.0.4",
+      "resolved": "https://registry.npmjs.org/string-similarity/-/string-similarity-4.0.4.tgz",
+      "integrity": "sha512-/q/8Q4Bl4ZKAPjj8WerIBJWALKkaPRfrvhfF8k/B23i4nzrlRj2/go1m90In7nG/3XDSbOo0+pu6RvCTM9RGMQ=="
+    },
     "string-width": {
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",

package.json

@@ -172,6 +172,7 @@
     "react-dom": "16.13.1",
     "selenium": "^2.20.0",
     "signale": "^1.4.0",
+    "string-similarity": "^4.0.4",
     "time-stamp": "^2.2.0",
     "tslib": "^2.3.0",
     "web3": "1.2.4",