Meteor TypeError: undefined is not a function

In Meteor, I was adding a new mongo collection using the following code:

 export const Areas = new Mongo.collection('areas');  

The app restarted and I got the following error:

 TypeError: undefined is not a function  
   at meteorInstall.imports.api.documents.js (imports/api/documents.js:8:22)  
   at fileEvaluate (packages/modules-runtime/.npm/package/node_modules/install/install.js:141:1)  
   at require (packages/modules-runtime/.npm/package/node_modules/install/install.js:75:1)  
   at meteorInstall.server.main.js (server/main.js:2:1)  
   at fileEvaluate (packages/modules-runtime/.npm/package/node_modules/install/install.js:141:1)  
   at require (packages/modules-runtime/.npm/package/node_modules/install/install.js:75:1)  
   at C:\Users\Philip\doc-revision\.meteor\local\build\programs\server\app\app.js:240:1  
   at C:\Users\Philip\doc-revision\.meteor\local\build\programs\server\boot.js:283:10  
   at Array.forEach (native)  
   at Function._.each._.forEach (C:\Users\Philip\AppData\Local\.meteor\packages\meteor-tool\1.3.2_4\mt-os.windows.x86_32\dev_bundle\server-lib\node_modules\underscore\underscore.js:79:11)  

It turns out that the word 'collection' should have been 'Collection'. This one was difficult to spot, but I eventual found it. The following code fixes the error

 export const Areas = new Mongo.Collection('areas');