Returns the head of an array.
arr
is truthy and has a length
property.arr[0]
if possible to return the first element, otherwise return undefined
.const head = arr => (arr && arr.length ? arr[0] : undefined);
head([1, 2, 3]); // 1
head([]); // undefined
head(null); // undefined
head(undefined); // undefined
Snippet collection
Learn a handful of awesome tips and tricks that you can leverage in your code to make array manipulation a breeze.
JavaScript, Array
Creates an array of elements, ungrouping the elements in an array produced by zip and applying the provided function.
JavaScript, Array
Mutates the original array to filter out the values specified, based on a given iterator function.
JavaScript, Array
Converts an array of objects to a comma-separated values (CSV) string that contains only the columns
specified.