Learn ECMAScript - Second Edition

Default values for variables

You can also provide default values for the variables if the object property is undefined while destructuring. The following example demonstrates this:

   let {a, b, c = 3} = {a: "1", b: "2"};
   console.log(c); //Output "3"

Some property names are constructed dynamically using expressions. In this case, to extract the property values, we can use the [ ] token to provide the property name with an expression. The following example demonstrates this:

   let {["first"+"Name"]: x} = { firstName: "Eden" };
   console.log(x); //Output "Eden"