Invariant ES6

invariant.js

const invariant = (condition, format, ...args) => {
  if (!condition) {
    if (!format) {
      throw new Error('General error occured.');
    }

    let i = 0;

    throw new Error(format.replace(/%s/g, () => args[i++]));
  }
};

invariant(
  1 > 2, 
  'Hello from error. %s %s %s %s %s %s',
  1, 2, 3, 4, 5, 6
);

// Results to
// > Uncaught Error: Hello from error. 1 2 3 4 5 6