how to use `??` operator javascript code example
Example 1: javascript ... operator
//The operator ... is part of the array destructuring.
//It's used to extract info from arrays to single variables.
//The operator ... means "the rest of the array".
var [head, ...tail] = ["Hello", "I" , "am", "Sarah"];
console.log(head);//"Hello"
console.log(tail);//["I", "am", "Sarah"]
//It can be used to pass an array as a list of function arguments
let a = [2,3,4];
Math.max(a) //--> NaN
Math.max(...a) //--> 4
Example 2: what does -= mean in JavaScript
/* JavaScript shorthand -=
-= is shorthand to subtract something from a
variable and store the result as that same variable.
*/
// The standard syntax:
var myVar = 5;
console.log(myVar) // 5
var myVar = myVar - 3;
console.log(myVar) // 2
// The shorthand:
var myVar = 5;
console.log(myVar) // 5
var myVar -= 3;
console.log(myVar) // 2