create dev webpack config for non-minified version

package.json

@@ -1,8 +1,9 @@
 {
   "scripts": {
     "build": "npm run lint && npm run clean && npm run webpack",
-    "build:dev": "npm run lint && npm run clean && npm run webpack && npm run package:dev",
+    "build:dev": "npm run lint && npm run clean && npm run webpack:dev && npm run package:dev",
     "webpack": "webpack --progress --colors --config webpack.config.js --output-path ./dist -p",
+    "webpack:dev": "webpack --progress --colors --config webpack.dev.js --output-path ./dist -p",
     "postbuild": "npm run package",
     "package": "tfx extension create  --rev-version",
     "package:dev": "tfx extension create --overrides-file vss-extension.dev.json --rev-version",
@@ -20,7 +21,8 @@
     "tslint-loader": "^3.6.0",
     "typescript": "^2.8.3",
     "webpack": "^4.16.3",
-    "webpack-cli": "^3.1.0"
+    "webpack-cli": "^3.1.0",
+    "webpack-merge": "^4.1.4"
   },
   "dependencies": {
     "@types/jquery": "^2.0.34",

vss-extension.json

@@ -1,7 +1,7 @@
 {
   "manifestVersion": 1,
   "id": "wiprint",
-  "version": "2.2.40",
+  "version": "2.2.45",
   "name": "Work Item Print",
   "scopes": ["vso.work", "vso.extension.data_write"],
   "description": "Print work items from query toolbar or context menu.",

webpack.config.js

@@ -2,7 +2,6 @@ var path = require("path");
 var webpack = require("webpack");
 
 module.exports = {
-    mode: "none",
     target: "web",
     entry: {
         wiprint: "./src/wiprint.ts",

webpack.dev.js

@@ -0,0 +1,16 @@
+var path = require("path");
+var webpack = require("webpack");
+
+const merge = require('webpack-merge');
+const common = require('./webpack.config.js');
+
+module.exports = merge(common, {
+    mode: 'development',
+    devtool: 'inline-source-map',
+    devServer: {
+        contentBase: './dist'
+    },
+    optimization: {
+        minimize: false
+    }
+});