TypeScript Iterators and Generators

TypeScript has some built in types like Array, String, Int32Array, Uint32Array, etc. support iteration because they have implemented Symbol.iterator property. In order to perform iteration on custom object, object must implement Symbol.Iterator property.

TypeScript For..Of Statement

The for..of loop work with iterable object like array by invoking Symbol.Iterator property and return value of iterable objects. For Example:

TypeScript For..Of Example 1

class Customer {
	Display():number
	{
       let numbers = [1, 2, 3,4,5,6,7,8,9,10];
        var s : any = "";
        var o = 0;
         for (let num of numbers) {
          s = s + "\n Array Value is - " + num;
         }
        return s;    
	}
}

Try it Yourself

TypeScript For..In Statement

The for..of loop work with any iterable object and return key of iterable objects. For Example:

TypeScript For..Of Example 2

class Customer {
	Display():number
	{
       let numbers = [1, 2, 3,4,5,6,7,8,9,10];
        var s : any = "";
        var o = 0;
         for (let num in numbers) {
          s = s + "\n Array Value is - " + num;
         }
        return s;    
	}
}

Try it Yourself