API Task

API Call

Load the rest countries’ data using your HTML and script.js file and run a for loop on the data and print all the country names in the console.

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🔽 Code Snippet Below

Blog Write-up

Give a write-up on the Difference between copy by value and copy by reference.

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Reference

How to copy by value a composite datatype (array+objects).

🔽 Code Snippet & Explaination

Rest countries’ API

https://restcountries.eu/rest/v2/all HTTP end point

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request.onload = function() {

var data = JSON.parse(this.response)

   for(i=0;i<data.length;i++){
      console.log(data[i].name)
   }
}
mark:1,5-7

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request.onload = function() {

var data = JSON.parse(this.response)

   for(i=0;i<data.length;i++){
      console.log(data[i].name)
   }
}

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Output

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Copy by value a composite data type?

There are 3 ways to copy by value for composite data types.

1. Using the spread (...) operator

Spread operator allows an iterable to expand in places where 0+ arguments are expected. It is mostly used in the variable array where there is more than 1 values are expected. It allows us the privilege to obtain a list of parameters from an array.Using spread will clone your object. Note this will be a shallow copy.

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let A= [1, 2, 3];
B= [...A];

console.log(A, B) // [1, 2, 3] [1, 2, 3]
B[1]= 8;

console.log(A, B) // [1, 2, 3] [1, 8, 3]

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2. Using the Object.assign() method

The Object.assign() method copies all enumerable own properties from one or more source objects to a target object. It returns the target object. Note this will be a shallow copy.

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let A= [1, 2, 3];
B= Object.assign([], A);

console.log(A, B) // [1, 2, 3] [1, 2, 3]
B[1]= 81;

console.log(A, B) // [1, 2, 3] [1, 81, 3]

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3. Using the JSON.stringify() and JSON.parse() methods

The JSON object, available in all modern browsers, has two useful methods to deal with JSON-formatted content: parse and stringify. JSON.parse() takes a JSON string and transforms it into a JavaScript object. JSON.stringify() takes a JavaScript object and transforms it into a JSON string.Using JSON.parse() and JSON.stringify() for copy performs deep copy.

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let A= [1, 2, 3];
B= JSON.parse(JSON.stringify(A));

console.log(A, B) // [1, 2, 3] [1, 2, 3]
B[1]= 88;

console.log(A, B) // [1, 2, 3] [1, 88, 3]

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