Update example in examples folder and README to conform to latest API changes and be more approachable and explicit

holgerd77 · holgerd77 · commit 2624092bfa3c · 2019-06-07T10:12:18.000+02:00
diff --git a/README.md b/README.md
@@ -48,20 +48,33 @@ Have a look at the corresponding issue to follow the discussion and current stat
 # USAGE
 
 ```javascript
-var VM = require('ethereumjs-vm')
+const BN = require('bn.js')
+var VM = require('ethereumjs-vm').default
 
-//create a new VM instance
-var vm = new VM()
-var code =
-  '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'
+// Create a new VM instance
+// For explicity setting the HF use e.g. `new VM({ hardfork: 'petersburg' })`
+const vm = new VM()
+
+const STOP = '00'
+const ADD = '01'
+const PUSH1 = '60'
+
+// Note that numbers added are hex values, so '20' would be '32' as decimal e.g.
+const code = [PUSH1, '03', PUSH1, '05', ADD, STOP]
+
+vm.on('step', function(data) {
+  console.log(`Opcode: ${data.opcode.name}\tStack: ${data.stack}`)
+})
 
 vm.runCode(
   {
-    code: Buffer.from(code, 'hex'), // code needs to be a Buffer
-    gasLimit: Buffer.from('ffffffff', 'hex'),
+    code: Buffer.from(code.join(''), 'hex'),
+    gasLimit: new BN(0xffff),
   },
   function(err, results) {
-    console.log('returned: ' + results.return.toString('hex'))
+    console.log('Returned : ' + results.return.toString('hex'))
+    console.log('gasUsed  : ' + results.gasUsed.toString())
+    console.log('Error    : ' + err)
   },
 )
 ```
diff --git a/examples/run-code-browser/README.md b/examples/run-code-browser/README.md
@@ -1,20 +1,38 @@
-## prerequisite
+# Build
 
+Build the project from the console:
+
+```shell
+npm run build:dist
+```
+
+This will create a new folder `dist/`.
+
+# Run Example in Node
+
+```shell
+node index.js
 ```
+
+# Run Example in a Browser
+
+## Prerequisites
+
+```shell
 $ npm install -g browserify http-server
 ```
 
 ## Instruction
 
 Run command
 
-```
+```shell
 $ browserify index.js -o bundle.js
 ```
 
 Then host this folder in a web server
 
-```
+```shell
 $ http-server
 ```
 
diff --git a/examples/run-code-browser/index.js b/examples/run-code-browser/index.js
@@ -7,23 +7,29 @@
  * and then load this folder onto a HTTP WebServer (e.g.
  * using node-static or `python -mSimpleHTTPServer`).
  */
-var Buffer = require('safe-buffer').Buffer // use for Node.js <4.5.0
-var VM = require('../../index.js')
+const BN = require('bn.js')
+const VM = require('../../dist/index.js').default
 
-// create a new VM instance
-var vm = new VM()
+// Create a new VM instance
+// For explicity setting the HF use e.g. `new VM({ hardfork: 'petersburg' })`
+const vm = new VM()
 
-var code = '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'
+const STOP  = '00'
+const ADD   = '01'
+const PUSH1 = '60'
+
+// Note that numbers added are hex values, so '20' would be '32' as decimal e.g.
+const code = [PUSH1, '03', PUSH1, '05', ADD, STOP]
 
 vm.on('step', function (data) {
-  console.log(data.opcode.name)
+  console.log(`Opcode: ${data.opcode.name}\tStack: ${data.stack}`)  
 })
 
 vm.runCode({
-  code: Buffer.from(code, 'hex'),
-  gasLimit: Buffer.from('ffffffff', 'hex')
+  code: Buffer.from(code.join(''), 'hex'),
+  gasLimit: new BN(0xffff)
 }, function (err, results) {
-  console.log('returned: ' + results.return.toString('hex'))
-  console.log('gasUsed: ' + results.gasUsed.toString())
-  console.log(err)
+  console.log('Returned : ' + results.return.toString('hex'))
+  console.log('gasUsed  : ' + results.gasUsed.toString())
+  console.log('Error    : ' + err)
 })
