sum of all elements in array javascript

JavaScript
console.log(
  [1, 2, 3, 4].reduce((a, b) => a + b, 0)
)
console.log(
  [].reduce((a, b) => a + b, 0)
)const arrSum = arr => arr.reduce((a,b) => a + b, 0)arrSum = function(arr){  return arr.reduce(function(a,b){    return a + b  }, 0);}
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