It is very hard to tell from the error message which provider causes this issue. The way I managed to debug this is the following:
- I went into the node_modules@angular\compiler\bundles\compiler.umd.js file
- I found the line where it says: “Encountered undefined provider! Usually this means you have a circular dependencies. This might be caused by using ‘barrel’ index.ts files.”
- One line before I added
console.log('type', type);in order to see in which file is the undefined provider (You can also console log other relevant variables there). - In the relevant file I found the ‘barrel’ import that caused the issue, and replaced it with exact file path import.