shim: Factor xml2Json

Making this optional to prevent loading XML library when unused.

.ava.json

@@ -1,3 +1,6 @@
 {
-    "verbose": true
+    "verbose": true,
+    "require": [
+        "@babel/register"
+    ]
 }

.babelrc

@@ -0,0 +1,5 @@
+{
+    "presets": [
+        "@babel/preset-env"
+    ]
+}

lib/shim/core.js

@@ -390,17 +390,6 @@ function exposePm () {
 }
 
 /* Conversion */
-function xml2Json (xml) {
-  const xml2js = require('./xml2js.js')
-  let json
-  xml2js.parseString(xml, { async: false }, (err, result) => {
-    if (err) {
-      throw err
-    }
-    json = result
-  })
-  return json
-}
 function xmlToJson (xml) {
   throw new Error('Deprecated function xmlToJson not supported')
 }
@@ -443,7 +432,6 @@ Object.defineProperties(global, {
 Object.assign(global, {
   postman,
   require,
-  xml2Json,
   xmlToJson
 })
 exposePm()

lib/shim/xml2Json.js

@@ -0,0 +1,14 @@
+import xml2js from '../xml2js.js'
+
+function xml2Json (xml) {
+  let json
+  xml2js.parseString(xml, { async: false }, (err, result) => {
+    if (err) {
+      throw err
+    }
+    json = result
+  })
+  return json
+}
+
+global.xml2Json = xml2Json

package.json

@@ -36,6 +36,8 @@
         "verror": "^1.10.0"
     },
     "devDependencies": {
+        "@babel/preset-env": "^7.3.4",
+        "@babel/register": "^7.0.0",
         "ava": "^1.2.1",
         "cross-env": "^5.2.0",
         "mock-require": "^3.0.3",

test/com/shim/convert.js

@@ -2,12 +2,13 @@
 
 import test from 'ava'
 import mockRequire from 'mock-require'
+import 'shim/core'
 
 const Reset = Symbol.for('reset')
 
 test.before(t => {
   mockRequire('../../../lib/xml2js.js', 'xml2js')
-  require('shim/core')
+  require('shim/xml2Json')
 })
 
 test.beforeEach(t => {