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JavaScript: Extract a specific number of characters from a string

JavaScript String: Exercise-4 with Solution

Write a JavaScript function to extract a specified number of characters from a string.

Pictorial Presentation:

JavaScript: Extract a specific number of characters from a string

Test Data :
console.log(truncate_string("Robin Singh",4));
"Robi"

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Extract a specific number of characters from a string</title>
</head>
<body>
</body>
</html>

JavaScript Code:

truncate_string = function (str1, length) {
  
    if ((str1.constructor === String) && (length>0)) {
        return str1.slice(0, length);
    }
};
console.log(truncate_string("Robin Singh",4));

Sample Output:

Robi

Flowchart:

Flowchart: JavaScript- Extract a specific number of characters from a string

Live Demo:

See the Pen JavaScript Extract a specific number of characters from a string - string-ex-4 by w3resource (@w3resource) on CodePen.


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Next: Write a JavaScript function to convert a string in abbreviated form.

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JavaScript: Tips of the Day

var functionName = function() {} vs function functionName() {}

The difference is that functionOne is a function expression and so only defined when that line is reached, whereas functionTwo is a function declaration and is defined as soon as its surrounding function or script is executed (due to hoisting).

For example, a function expression:

// TypeError: functionOne is not a function
functionOne();

var functionOne = function() {
  console.log("Hello!");
};

Historically, function declarations defined within blocks were handled inconsistently between browsers. Strict mode (introduced in ES5) resolved this by scoping function declarations to their enclosing block.

'use strict';    
{ // note this block!
  function functionThree() {
    console.log("Hello!");
  }
}
functionThree(); // ReferenceError

Ref: https://bit.ly/2zMAj1O