This post is a part 10 of ECMAScript 6 Complete Tutorial post series.
ECMAScript 6 specification introduced a new JavaScript feature called as JavaScript Generators. JavaScript’s yield keyword and function*() syntax together make JS Generators.
In nutshell JavaScript generators provide a new way for functions to return a collection and also a new way of looping(or iterating) through the elements of the returned collection.
Earlier to JavaScript Generators you would do something like this
function collection_name()
{
return [1, 3, 5, 7];
}
var collection = collection_name();
for(var iii = 0; iii < collection.length; iii++)
{
console.log(collection[iii]);
}
{
return [1, 3, 5, 7];
}
var collection = collection_name();
for(var iii = 0; iii < collection.length; iii++)
{
console.log(collection[iii]);
}
Here is how you can do the same using Generators
function* collection_name()
{
yield 1;
yield 3;
yield 5;
yield 7;
}
for(var iii of collection_name())
{
console.log(iii);
}
{
yield 1;
yield 3;
yield 5;
yield 7;
}
for(var iii of collection_name())
{
console.log(iii);
}
Internally JavaScript creates a object with Symbol.iterator property from the yielded values which is what for of construct needs for iterating a collection.
