JavaScript Commands

The language of the web, in browsers and server runtimes.All JavaScript pages

javascript deep clone an object with structuredClone()structuredClone(obj) deep-copies objects in JavaScript, keeping Date, Map, Set and circular references. Why spread is shallow and when DataCloneError appears.
javascript format date as YYYY-MM-DDFormat a JavaScript Date as YYYY-MM-DD: toISOString for UTC, local getters with padStart, Intl.DateTimeFormat for a time zone, and the off-by-one-day trap.
javascript remove duplicates from arrayRemove duplicates from a JavaScript array with [...new Set(arr)], keep first-seen order, handle NaN, and deduplicate arrays of objects by a key with a Map.
javascript sort array of objects by propertySort an array of objects by a property in JavaScript with sort() or toSorted() and a compare function: numbers, strings with localeCompare, several keys.