Update create-arrays.md

Author: basarat

docs/tips/create-arrays.md

@@ -12,3 +12,10 @@ If you want to create an array pre-filled with some content use the ES6 `Array.p
 const foo:string[] = new Array(3).fill('');
 console.log(foo); // ['','',''];
 ```
+
+If you want to create an array of a predefined length with calls you can use the spread operator: 
+
+```ts
+const someNumbers = [...new Array(3)].map((_,i) => i * 10);
+console.log(someNumbers); // [0,10,20];
+```