Make helpers a class and provide eth object to helpers

src/evaluator/index.js

@@ -7,7 +7,7 @@ const Eth = require('web3-eth')
 const Web3Utils = require('web3-utils')
 const BN = require('bn.js')
 const types = require('../types')
-const helpers = require('../helpers')
+const { Helpers } = require('../helpers')
 
 /**
  * A value coupled with a type
@@ -64,6 +64,7 @@ class Evaluator {
     this.bindings = bindings
     this.eth = new Eth(ethNode || 'https://mainnet.infura.io')
     this.to = to && new TypedValue('address', to)
+    this.helpers = new Helpers(this.eth)
   }
 
   /**
@@ -243,12 +244,12 @@ class Evaluator {
     if (node.type === 'HelperFunction') {
       const helperName = node.name
 
-      if (!helpers.exists(helperName)) {
+      if (!this.helpers.exists(helperName)) {
         this.panic(`${helperName} helper function is not defined`)
       }
 
       const inputs = await this.evaluateNodes(node.inputs)
-      const { type, value } = await helpers.execute(helperName, inputs)
+      const { type, value } = await this.helpers.execute(helperName, inputs)
 
       return new TypedValue(type, value)
     }

src/helpers/echo.js

@@ -1,3 +1,3 @@
-module.exports = async (node, repeat = 1) => {
-  return { type: 'string', value: node.value.repeat(repeat) }
+module.exports = () => async (echo, repeat = 1) => {
+  return { type: 'string', value: echo.repeat(repeat) }
 }

src/helpers/formatDate.js

@@ -1,3 +1,3 @@
-module.exports = async (timestamp, format='MM-DD-YYYY') => {
+module.exports = () => async (timestamp, format='MM-DD-YYYY') => {
   return { type: 'string', value: timestamp } // TODO
 }

src/helpers/index.js

@@ -1,17 +1,31 @@
 const formatDate = require('./formatDate')
 const echo = require('./echo')
+const tokenAmount = require('./tokenAmount')
 
-module.exports = {
-  helpers: {
-    formatDate,
-    echo,
-  },
+const defaultHelpers = {
+  formatDate,
+  echo,
+  tokenAmount,
+}
+
+class Helpers {
+  constructor (eth, userHelpers = {}) {
+    this.eth = eth
+    this.helpers = { ...defaultHelpers, ...userHelpers }
+  }
 
   exists (helper) {
     return !!this.helpers[helper]
-  },
+  }
 
   execute (helper, inputs) {
-    return this.helpers[helper](...inputs)
+    inputs = inputs.map(input => input.value) // pass values directly
+    return this.helpers[helper](this.eth)(...inputs)
   }
+}
+
+module.exports = {
+  Helpers,
+
+  defaultHelpers
 }