improve error message for primitive properties used as a relation/function

Author: usu

package.json

@@ -5,6 +5,7 @@
   "main": "dist/bundle.js",
   "scripts": {
     "build": "cross-env NODE_ENV=production webpack",
+    "build-dev": "cross-env NODE_ENV=development webpack",
     "clean": "cross-env rimraf dist coverage lib",
     "coverage": "cross-env npm run build && jest --coverage",
     "lint": "cross-env eslint src --ext .js,.ts",
@@ -83,4 +84,4 @@
     "webpack-cli": "4.9.1",
     "webpack-node-externals": "3.0.0"
   }
-}
+}

src/LoadingStoreValue.ts

@@ -59,7 +59,16 @@ class LoadingStoreValue implements Resource {
 
         // Proxy to all other unknown properties: return a function that yields another LoadingStoreValue
         const loadProperty = loadResource.then(resource => resource[prop])
-        const result = templateParams => new LoadingStoreValue(loadProperty.then(property => property(templateParams)._meta.load))
+
+        const result = templateParams => new LoadingStoreValue(loadProperty.then(property => {
+          try {
+            return property(templateParams)._meta.load
+          } catch (e) {
+            throw new Error(`Property '${prop.toString()}' on resource ${absoluteSelf} was used like a relation, but no relation with this name was returned by the API (actual return value: ${JSON.stringify(property)})`)
+          }
+        }
+        ))
+
         result.toString = () => ''
         return result
       }

webpack.config.js

@@ -1,6 +1,6 @@
-var path = require('path')
-var webpack = require('webpack')
-var nodeExternals = require('webpack-node-externals')
+const path = require('path')
+const webpack = require('webpack')
+const nodeExternals = require('webpack-node-externals')
 
 module.exports = {
   devtool: 'source-map',
@@ -16,7 +16,7 @@ module.exports = {
   plugins: [
     new webpack.DefinePlugin({
       'process.env': {
-        NODE_ENV: JSON.stringify('production')
+        NODE_ENV: JSON.stringify(process.env.NODE_ENV)
       }
     })
   ],