Page 115 - JavaScript

suspect there is a chance the array has cyclic references (a reference to an array that contains a
reference to itself)

a = [0] ;
a[1] = a;
b = [0, a];
compareArrays(a, b); // throws RangeError: Maximum call stack size exceeded

Note: The function uses the strict equality operator === to compare non array items {a:
0} === {a: 0} is false

Destructuring an array

6

An array can be destructured when being assigned to a new variable.

const triangle = [3, 4, 5];
const [length, height, hypotenuse] = triangle;

length === 3; // → true
height === 4; // → true
hypotneuse === 5; // → true

Elements can be skipped

const [,b,,c] = [1, 2, 3, 4];

console.log(b, c); // → 2, 4

Rest operator can be used too

const [b,c, ...xs] = [2, 3, 4, 5];
console.log(b, c, xs); // → 2, 3, [4, 5]

An array can also be destructured if it's an argument to a function.

function area([length, height]) {
return (length * height) / 2;
}

const triangle = [3, 4, 5];

area(triangle); // → 6

Notice the third argument is not named in the function because it's not needed.

Learn more about destructuring syntax.

Removing duplicate elements

https://riptutorial.com/ 72