head

JavaScript, Array

Returns the head of an array.

  • Check if arr is truthy and has a length property.
  • Use 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

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