JavaScript: Get the minimum value of an array, after mapping each element to a value using the provided function

JavaScript fundamental (ES6 Syntax): Exercise-177 with Solution

Minimum Value After Mapping

Write a JavaScript program to get the minimum value of an array, after mapping each element to a value using the provided function.

• Use Array.prototype.map() to map each element to the value returned by fn.
• Use Math.min() to get the minimum value.

Sample Solution:

JavaScript Code:

// Define a function 'minBy' that takes an array 'arr' and a function 'fn'
const minBy = (arr, fn) =>
  // Use the spread operator to pass each element of the mapped array as arguments to Math.min
  Math.min(
    // Map each element of the input array 'arr' to the value returned by 'fn' or the value of 'n' property if 'fn' is a string
    ...arr.map(typeof fn === 'function' ? fn : val => val[fn])
  );

// Log the minimum value of the 'n' property of objects in the array [{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }]
console.log(minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n));
// Log the minimum value of the 'n' property of objects in the array [{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }]
console.log(minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'));

Output:

2
2

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-177-1 by w3resource (@w3resource) on CodePen.

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