JavaScript: Return the minimum-maximum value of an array, after applying the provided function to set comparing rule

JavaScript fundamental (ES6 Syntax): Exercise-15 with Solution

Min-Max Value of Array with Function

Write a JavaScript program to return the minimum-maximum value of an array, after applying the provided function to set a comparing rule.

• Use Array.prototype.reduce() in combination with the comparator function to get the appropriate element in the array.
• Omit the second argument, comparator, to use the default one that returns the minimum element in the array.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
// Define a function called `reduce_Which` that returns the minimum element of an array based on a provided comparator function.
const reduce_Which = (arr, comparator = (a, b) => a - b) =>
  arr.reduce((a, b) => (comparator(a, b) >= 0 ? b : a)); // Reduce the array and return the element that satisfies the comparator

// Example usage
console.log(reduce_Which([1, 3, 2])); // Returns the minimum element of the array
console.log(reduce_Which([10, 30, 20], (a, b) => b - a)); // Returns the maximum element of the array
console.log(reduce_Which(
  [{ name: 'Kevin', age: 16 }, { name: 'John', age: 20 }, { name: 'Ani', age: 19 }],
  (a, b) => a.age - b.age)); // Returns the object with the minimum age

Output:

1
30
{"name":"Kevin","age":16}

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-1-15 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that applies a given function to each element of an array and returns both the minimum and maximum results.
• Write a JavaScript function that maps an array using a comparator function, then extracts the min and max values.
• Write a JavaScript program that finds the minimum and maximum of an array after transforming its elements via a provided callback.

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