.babelrc

{
  "presets": [
    ["@babel/preset-env", {
      "targets": {
        "node": "current",
        "browsers": [ "last 2 versions", "safari >= 7", "> 5%" ]
      },
      "modules": "umd",
      "useBuiltIns": "usage",
      "corejs": 2
    }],
    "@babel/preset-typescript"
  ],
  "plugins": [
    "angularjs-annotate",
    ["module-resolver", {
      "root": [
        "src/main/assets/modules",
        "src/main/assets/js",
        "src/main/assets/style",
        "node_modules"
      ]
      }],
    ["@babel/plugin-transform-runtime", {
      "corejs": 2,
      "helpers": false,
      "regenerator": true
      }],
    "@babel/plugin-proposal-async-generator-functions",
    "@babel/plugin-proposal-class-properties",
    "@babel/plugin-proposal-object-rest-spread",
    "@babel/plugin-transform-destructuring",
    "@babel/plugin-transform-for-of",
    "@babel/plugin-transform-modules-commonjs",
    "@babel/plugin-transform-regenerator"
  ]
}

constructor-subclass-initialization.ts

abstract class ParentClass {
  private hash?: string;

  constructor() {
    this.generateHash();
  }

  protected generateHash() {
    this.hash = Math.random().toString(6);
    this.onNewHash(this.hash);
  }

  protected onNewHash(newHash?: string) {
  }
}

class SubClass extends ParentClass {
  public computedString?: string;

  constructor() {
    super();
  }

  protected onNewHash(newHash?: string) {
    super.onNewHash(newHash);
    this.computedString = 'Basic ' + newHash;
  }
}

const sc = new SubClass();
console.log(sc.computedString);

tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "experimentalDecorators": true,
    "sourceMap": true,
    "allowJs": true,
    "lib": [ "es6", "dom" ],
    "skipLibCheck": true,
    "outDir": "dist"
  },
  "include": [
    "src"
  ]
}