js/tsconfig/tsconfig.es2015.cls.json

// Compiler configuration to build the ES2015 Closure Compiler target
{
  "extends": "./tsconfig.base.json",
  "compilerOptions": {
    "target": "ES2015",
    "module": "es2015",
    "declaration": false,
    "noEmitHelpers": true,
    "importHelpers": true
  }
}