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JavaScript: Gather and display infromation from an object

JavaScript Object: Exercise-4 with Solution

Write a JavaScript program to display the reading status (i.e. display book name, author name and reading status) of the following books.

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Reading status of a book library</title>
</head>
<body>
</body>
</html>

JavaScript Code:

var library = [ 
    {
        title: 'Bill Gates',
        author: 'The Road Ahead',
        readingStatus: true
    },
    {
        title: 'Steve Jobs',
        author: 'Walter Isaacson',
        readingStatus: true
    },
    {
        title: 'Mockingjay: The Final Book of The Hunger Games',
        author: 'Suzanne Collins',
        readingStatus: false
    }];

for (var i = 0; i < library.length; i++) 
   {
    var book = "'" + library[i].title + "'" + ' by ' + library[i].author + ".";
    if (library[i].readingStatus) {
      console.log("Already read " + book);
    } else
    {
     console.log("You still need to read " + book);
    }
   }
   

Sample Output:

Already read 'Bill Gates' by The Road Ahead.
Already read 'Steve Jobs' by Walter Isaacson.
You still need to read 'Mockingjay: The Final Book of The Hunger Games' by Suzanne Collins.

Flowchart:

Flowchart: JavaScript - Gather and display infromation from an object.

Live Demo:

See the Pen javascript-object-exercise-4 by w3resource (@w3resource) on CodePen.


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JavaScript: Tips of the Day

How to remove a specific item from an array?

Find the index of the array element you want to remove using indexOf, and then remove that index with splice.

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

const array = [2, 5, 9];

console.log(array);

const index = array.indexOf(5);
if (index > -1) {
  array.splice(index, 1);
}

// array = [2, 9]
console.log(array);

The second parameter of splice is the number of elements to remove. Note that splice modifies the array in place and returns a new array containing the elements that have been removed.

For the reason of completeness, here are functions. The first function removes only a single occurrence (i.e. removing the first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:

function removeItemOnce(arr, value) {
  var index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

function removeItemAll(arr, value) {
  var i = 0;
  while (i < arr.length) {
    if (arr[i] === value) {
      arr.splice(i, 1);
    } else {
      ++i;
    }
  }
  return arr;
}
//Usage
console.log(removeItemOnce([2,5,9,1,5,8,5], 5))
console.log(removeItemAll([2,5,9,1,5,8,5], 5))

Ref: https://bit.ly/2N9nKRp