no need for this. I can use Tern.java.

Could typescript.java provide also code completion for js-files

Yes it should work. If it doesn't work, it's perhaps your project has JSDT nature. If I rememeber you must activate that with TypeScript preferences (from global / window preferences)

code completion only works if I rename my js-file to a ts-file.

For js-files, I have no code completion.

I have this settings:

• Preferences->..->Typescript->"Use Salsa as JavaScript Inference" (enabled)
• Typescript.java 1.4
• JBoss Tools Java Standard Tools provides an adapter to Tern.java project. version 3.8
• enabled tern-repository (Preferences->..->Tern->Development->Repository): EcmaScript 6, es_modules, Browser, Browser_extension, Gulp, Node.js, Outline, Webpack
• Eclipse Oxygen.1a Release (4.7.1a)

My .tern-config:

{
  "plugins": {
    "guess-types": {
      
    },
    "outline": {
      
    },
    "webpack": {
      
    },
    "es_modules": {
      
    },
    "node": {
      
    },
    "gulp": {
      
    },
    "browser-extension": {
      
    },
    "angular": {
      
    }
  },
  "libs": [
    "ecma5",
    "ecma6",
    "browser"
  ]
}

My "ts.eclipse.ide.core.prefs" from within .settings-directory:

eclipse.preferences.version=1
nodeJSPath=/usr/local/bin/node
useNodeJSEmbedded=false
typeScriptBuildPath={"src/js/tsconfig.json"\:{}}

When editing a js-file, I have no code completion for any kind:

• No default Proposals
• No template Proposals
• No basic Proposals
• No tern completion Proposals
• No typescript Proposals

How can I force to have code completion with js-files the same as I have with ts-files?