Question

Give an example where do you really need semicolon?

Answer 1

It is recommended to use semicolons after every statement in JavaScript. For example, in the below case it throws an error ".. is not a function" at runtime due to missing semicolon.

// define a function
var fn = (function () {
  //...
})(
  // semicolon missing at this line

  // then execute some code inside a closure
  function () {
    //...
  }
)();

and it will be interpreted as

var fn = (function () {
  //...
})(function () {
  //...
})();

In this case, we are passing the second function as an argument to the first function and then trying to call the result of the first function call as a function. Hence, the second function will fail with a "... is not a function" error at runtime.