You can export a single class in TypeScript like this:

class Person {

  private firstName: string;
  private lastName: string;

  constructor(firstName: string, lastName: string) {
    this.firstName = firstName;
    this.lastName = lastName;
  }

  public getFullName() {
    return `${this.firstName} ${this.lastName}`;
  }
}

export = Person;

And here is how it's going to be used:

var Person = require('./dist/commonjs/Person.js');

var homer = new Person('Homer', 'Simpson');
var name = homer.getFullName();

console.log(name); // Homer Simpson

To be complete, here is my tsconfig.json (I am using TypeScript v2.0.3):

{
  "compilerOptions": {
    "module": "commonjs",
    "moduleResolution": "node",
    "outDir": "dist/commonjs",
    "rootDir": "src/ts",
    "target": "es5"
  },
  "exclude": [
    "dist",
    "node_modules"
  ]
}