Array.prototype.concat()
Array.prototype.concat() is a JavaScript method in the Array category. Merges two or more arrays into a new array. The syntax is array.concat(value1, ..., valueN). A typical example: [1, 2].concat([3, 4]) // [1, 2, 3, 4]. Its time complexity is O(n), which matters when it runs over large inputs. A close sibling is Array.prototype.map(), which creates a new array populated with the results of calling a provided function on every element. A close sibling is Array.prototype.filter(), which creates a new array with all elements that pass the test implemented by the provided function. A close sibling is Array.prototype.reduce(), which executes a reducer function on each element, resulting in a single output value. A close sibling is Array.prototype.forEach(), which executes a provided function once for each array element. More about this category: Array methods for manipulating arrays — map, filter, reduce, find, and more. Related Array methods: Array.prototype.map(), Array.prototype.filter(), Array.prototype.reduce(), Array.prototype.forEach(), Array.prototype.find(), Array.prototype.findIndex(), Array.prototype.findLast(), Array.prototype.some().