Question

Exercise 2

Using javascript (visual studio code)

(a) Write code that creates 5 item objects (records)

(b) Place the five item objects into an array

(c) Write a function that prints an array of your items it has one parameter an array of items

(d) Write a function that counts items that match some attribute value.

(e) Write a function that filters an array of items. It has three parameter an array of item, an attribute name and a value. It return a new array that contains a ‘shallow copy’ of the relevant items. (f) Write code that stores an item array as JSON text

(g) Write code that loads an item array from JSON text

(h) Write a function that filters an array of item, but this time it has two parameters, an array of items and a function f that stores the filter condition. Write test data that contains several test cases. For your test data use both traditional functions and arrow-functions (lambdas).

Exercise 2 (a) Write code that creates 5 item objects (records) (b) Place the five item objects into an array (c) Write a function that prints an array of your items it has one parameter an array of items (d) Write a function that counts items that match some attribute value. (e) Write a function that filters an array of items. It has three parameter an array of item, an attribute name and a value. It return a new array that contains a 'shallow copy of the relevant items. (f) Write code that stores an item array as JSON text (g) Write code that loads an item array from JSON text (h) Write a function that filters an array of item, but this time it has two parameters, an array of items and a function f that stores the filter condition. Write test data that contains several test cases. For your test data use both traditional functions and arrow-functions (lambdas).

Answer 1

Hi,

As HOMEWORKLIB expert guidelines I can choose to answer first 4 subparts of the question.

Here I have answered all expect last subpart.

Please find the script along with description below.

//Write code that creates 5 item objects (records)

//and Place the five item objects into an array

// I have taken name and age as properties of the object.

let Items = [

{

name: "AMRUTH",

age: 5

},

{

name: "raksha",

age: 10

},

{

name: "bandit",

age: 2

},

{

name: "queen",

age: 13

},

{

name: "raaku",

age: 15

}

];

//Write a function that prints an array of your items it has one parameter an array of items

function listItems(items)

{

let items_names = [];

for (let i=0; i<items.length; i+=1)

{

items_names.push(items[i].name);

}

return items_names;

}

//Write a function that counts items that match some attribute value.

function countNoOfItemswithID(age)

{

var count = 0;

for(var i = 0; i < Items.length; ++i)

{

if(Items[i].age == age)

count++;

}

console.log('number of the found elements: ' + count);

}

//Write a function that filters an array of items. It has three parameter an array of item, an attribute name and a value. It return a new array

//that contains a ‘shallow copy’ of the relevant items.

function getCopiedObject(items,name, age)

{

this.name = name;

this.age = age;

this.printItemInfo = function()

{

console.log(this.name);

console.log(this.age);

}

}

//Write code that stores an item array as JSON text

function convertToJsonText()

{

var jsonText = "JSON_TEXT = '"+JSON.stringify(Items)+"'";

console.log(jsonText);

}

//Write code that loads an item array from JSON text

function convertJsonTextToObject()

{

var jsonObject = "Array = [" +Items+"]";

jsonObject = "JSON Object = "+JSON.stringify(Object.assign({}, Items));

console.log(jsonObject);

}

console.log(listItems(Items));

console.log(countNoOfItemswithID(2));

//this is not logged sure it will print as undefined in logs.

var copiedObject = new getCopiedObject(Items,"AMRUTH", 5);

copiedObject.printItemInfo();

convertToJsonText();

convertJsonTextToObject();

output:

kindly upvote