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In short, this works:
[1, 2, 3].reduce(function (a, b) { return Math.max(a, b); });
=> 3
But this doesn't:
[1, 2, 3].reduce(Math.max);
=> NaN
Pure puzzlement.
This is in Firefox 3.5.9, which I presume is using the mozilla standard implementation of reduce, FWIW.
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Functions that operate on other functions, either by taking them as arguments or by returning them, are called higher-order functions.
Note: Functions such as filter(),map(),reduce(),some() etc, these all are example of Higher-Order Functions.
Let's look at an example of a higher order functionconst numbers = [1, 2, 3, 4, 5]; function addOne(array) { for (let i = 0; i < array. length; i++) { console. log(array[i] + 1); } } addOne(numbers); The function addOne() accepts an array, adds one to each number in the array, and displays it in the console.
Math.max can be used as a higher-order function. The problem is .reduce will call the function with 4 arguments:
Math.max(accumulator, value, index, the_array)
here is the_array is an array, so Math.max returns NaN. I don't think there's simpler way to discard the last 2 arguments.
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