JavaScript fundamental: Get a sorted array of objects ordered by properties and orders

JavaScript fundamental (ES6 Syntax): Exercise-37 with Solution

Write a JavaScript program to get a sorted array of objects ordered by properties and orders.

• Uses Array.prototype.sort(), Array.prototype.reduce() on the props array with a default value of 0.
• Use array destructuring to swap the properties position depending on the order supplied.
• If no orders array is supplied, sort by 'asc' by default.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
// Define a function 'orderBy' that takes three parameters: 'arr' (an array), 'props' (an array of property names), and 'orders' (an optional array of sort orders).
const orderBy = (arr, props, orders) =>
  // Create a new array by cloning 'arr', then sort it based on the given properties and orders.
  [...arr].sort((a, b) =>
    // Reduce the properties to a single value that represents the comparison result.
    props.reduce((acc, prop, i) => {
      if (acc === 0) {
        // Check if the current property should be sorted in descending order.
        const [p1, p2] = orders && orders[i] === 'desc' ? [b[prop], a[prop]] : [a[prop], b[prop]];
        // Compare the properties and update the accumulator accordingly.
        acc = p1 > p2 ? 1 : p1 < p2 ? -1 : 0;
      }
      return acc; // Return the final comparison result.
    }, 0) // Start with an initial value of 0 for the accumulator.
  );

// Define an array of user objects.
const users = [
  { name: 'fred', age: 48 },
  { name: 'barney', age: 36 },
  { name: 'fred', age: 40 }
];

// Test the 'orderBy' function with different property names and sort orders, then output the sorted arrays.
console.log(orderBy(users, ['name', 'age'], ['asc', 'desc']));  
console.log(orderBy(users, ['name', 'age']));

Output:

[{"name":"barney","age":36},{"name":"fred","age":48},{"name":"fred","age":40}]
[{"name":"barney","age":36},{"name":"fred","age":40},{"name":"fred","age":48}]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-1-37 by w3resource (@w3resource) on CodePen.

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