JavaScript: Pad a string on both sides with the specified character

JavaScript fundamental (ES6 Syntax): Exercise-38 with Solution

Pad String on Both Sides

Write a JavaScript program to pad a string on both sides with the specified character, if it's shorter than the specified length.

• Use String.prototype.padStart() and String.prototype.padEnd() to pad both sides of the given string.
• Omit the third argument, char, to use the whitespace character as the default padding character.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
// Define a function 'pad' that takes three parameters: 'str' (a string), 'length' (the desired length of the padded string), and 'char' (the padding character, default is a space).
const pad = (str, length, char = ' ') =>
  // Pad the string with the specified character using padStart and padEnd methods to achieve the desired length.
  str.padStart((str.length + length) / 2, char).padEnd(length, char);

// Test the 'pad' function with different inputs and output the padded strings.
console.log(pad('cat', 8));  
console.log(pad(String(42), 6, '0'));  
console.log(pad('foobar', 3));

Output:

  cat   
004200
foobar

Visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-1-38 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that pads a string on both sides with a specified character until it reaches a given length.
• Write a JavaScript function that centers a string by adding equal padding to the left and right using string.repeat().
• Write a JavaScript program that verifies the string’s current length and applies side padding if it is shorter than a target length.

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