Interesting JavaScript snippets

Array.prototype.some()

The some() method tests whether at least one element in the array passes the test implemented by the provided function. It returns true if, in the array, it finds an element for which the provided function returns true; otherwise it returns false.

const oneDomain = policyArr.some((item) => item === "block");
const allDomains = policyArr.every((item) => item === "block");
return { oneDomain, allDomains };

{ oneDomain: true, allDomains: false }

Object.keys()

The Object.keys() static method returns an array of a given object’s own enumerable string-keyed property names.

const domains = {
 "one.com": { policy: "block" },
 "two.com": { policy: "none" },
 "three.com": { policy: "none" },
}

const numDomains = Object.keys(domains).length; // O(1)