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JavaScript: Execute a provided function once for each array element, starting from the array's last element

JavaScript fundamental (ES6 Syntax): Exercise-76 with Solution

Write a JavaScript program to execute a provided function once for each array element, starting with the array's last element.

  • Use Array.prototype.slice() to clone the given array and Array.prototype.reverse() to reverse it.
  • Use Array.prototype.forEach() to iterate over the reversed array.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const forEachRight = (arr, callback) =>
  arr
    .slice(0)
    .reverse()
    .forEach(callback);
forEachRight([1, 2, 3, 4], val => console.log(val));

Sample Output:

4
3
2
1

Flowchart:

flowchart: Execute a provided function once for each array element, starting from the array's last element

Live Demo:

See the Pen javascript-basic-exercise-76-1 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

Parse an HTTP Cookie header string and return an object of all cookie name-value pairs

Example:

const parseCookie = str =>
  str
    .split(';')
    .map(v => v.split('='))
    .reduce((acc, v) => {
      acc[decodeURIComponent(v[0].trim())] = decodeURIComponent(v[1].trim());
      return acc;
    }, {});
console.log(parseCookie('foo=bar; equation=E%3Dmc%5E2')); // { foo: 'bar', equation: 'E=mc^2' }

Output:

[object Object] {
  equation: "E=mc^2",
  foo: "bar"
}

 

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