Can Make Arithmetic Progression From Sequence LeetCode solution in JavaScript

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var canMakeArithmeticProgression = function (arr) {
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  arr.sort(function (a, b) {
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    return a - b;
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  });
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  var dif = arr[1] - arr[0];
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  for (var i = 2; i < arr.length; i++) {
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    if (arr[i] - arr[i - 1] !== dif) {
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      return false;
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    }
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  }
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  return true;
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};