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JavaScript String - Exercises, Practice, Solution

JavaScript String [49 exercises with solution]

[An editor is available at the bottom of the page to write and execute the scripts.]

1. Write a JavaScript function to check whether an `input` is a string or not. Go to the editor
Test Data :
console.log(is_string('w3resource'));
true
console.log(is_string([1, 2, 4, 0]));
false
Click me to see the solution

2. Write a JavaScript function to check whether a string is blank or not. Go to the editor
Test Data :
console.log(is_Blank(''));
console.log(is_Blank('abc'));
true
false
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3. Write a JavaScript function to split a string and convert it into an array of words. Go to the editor
Test Data :
console.log(string_to_array("Robin Singh"));
["Robin", "Singh"]
Click me to see the solution

4. Write a JavaScript function to extract a specified number of characters from a string. Go to the editor
Test Data :
console.log(truncate_string("Robin Singh",4));
"Robi"
Click me to see the solution.

5. Write a JavaScript function to convert a string in abbreviated form. Go to the editor
Test Data :
console.log(abbrev_name("Robin Singh"));
"Robin S."
Click me to see the solution.

6. Write a JavaScript function to hide email addresses to protect from unauthorized user. Go to the editor
Test Data :
console.log(protect_email("[email protected]"));
"[email protected]"
Click me to see the solution.

7. Write a JavaScript function to parameterize a string. Go to the editor
Test Data :
console.log(string_parameterize("Robin Singh from USA."));
"robin-singh-from-usa"
Click me to see the solution.

8. Write a JavaScript function to capitalize the first letter of a string. Go to the editor
Test Data :
console.log(capitalize('js string exercises'));
"Js string exercises"
Click me to see the solution.

9. Write a JavaScript function to capitalize the first letter of each word in a string. Go to the editor
Test Data :
console.log(capitalize_Words('js string exercises'));
"Js String Exercises"
Click me to see the solution.

10. Write a JavaScript function that takes a string which has lower and upper case letters as a parameter and converts upper case letters to lower case, and lower case letters to upper case. Go to the editor
Test Data :
console.log(swapcase('AaBbc'));
"aAbBC"
Click me to see the solution.

11. Write a JavaScript function to convert a string into camel case.Go to the editor
Test Data :
console.log(camelize("JavaScript Exercises"));
console.log(camelize("JavaScript exercises"));
console.log(camelize("JavaScriptExercises"));
"JavaScriptExercises"
"JavaScriptExercises"
"JavaScriptExercises"
Click me to see the solution.

12. Write a JavaScript function to uncamelize a string. Go to the editor
Test Data :
console.log(uncamelize('helloWorld'));
console.log(uncamelize('helloWorld','-'));
console.log(uncamelize('helloWorld','_'));
"hello world"
"hello-world"
"hello_world"
Click me to see the solution.

13. Write a JavaScript function to concatenates a given string n times (default is 1). Go to the editor
Test Data :
console.log(repeat('Ha!'));
console.log(repeat('Ha!',2));
console.log(repeat('Ha!',3));
"Ha!"
"Ha!Ha!"
"Ha!Ha!Ha!"
Click me to see the solution.

14. Write a JavaScript function to insert a string within a string at a particular position (default is 1).Go to the editor
Test Data :
console.log(insert('We are doing some exercises.'));
console.log(insert('We are doing some exercises.','JavaScript '));
console.log(insert('We are doing some exercises.','JavaScript ',18));
"We are doing some exercises."
"JavaScript We are doing some exercises."
"We are doing some JavaScript exercises."
Click me to see the solution.

15. Write a JavaScript function to humanized number (Formats a number to a human-readable string.) with the correct suffix such as 1st, 2nd, 3rd or 4th. Go to the editor
Test Data :
console.log(humanize_format());
console.log(humanize_format(1));
console.log(humanize_format(8));
console.log(humanize_format(301));
console.log(humanize_format(402));
"1st"
"8th"
"301st"
"402nd"
Click me to see the solution.

16. Write a JavaScript function to truncates a string if it is longer than the specified number of characters. Truncated strings will end with a translatable ellipsis sequence ("…") (by default) or specified characters. Go to the editor
Test Data :
console.log(text_truncate('We are doing JS string exercises.'))
console.log(text_truncate('We are doing JS string exercises.',19))
console.log(text_truncate('We are doing JS string exercises.',15,'!!'))
"We are doing JS string exercises."
"We are doing JS ..."
"We are doing !!"
Click me to see the solution.

17. Write a JavaScript function to chop a string into chunks of a given length. Go to the editor
Test Data :
console.log(string_chop('w3resource'));
console.log(string_chop('w3resource',2));
console.log(string_chop('w3resource',3));
["w3resource"]
["w3", "re", "so", "ur", "ce"]
["w3r", "eso", "urc", "e"]
Click me to see the solution.

18. Write a JavaScript function to count the occurrence of a substring in a string. Go to the editor
Test Data :
console.log(count("The quick brown fox jumps over the lazy dog", 'the'));
Output :
2
console.log(count("The quick brown fox jumps over the lazy dog", 'fox',false));
Output :
1
Click me to see the solution.

19. Write a JavaScript function to escape a HTML string. Go to the editor
Test Data :
console.log(escape_HTML('<a href="javascript-string-exercise-17.php" target="_blank">'));
Output :
"&lt;a href=&quot;javascript-string-exercise-17.php&quot; target=&quot;_blank&quot;&gt;"
Click me to see the solution.

20. Write a JavaScript function that can pad (left, right) a string to get to a determined length. Go to the editor
Test Data :
console.log(formatted_string('0000',123,'l'));
console.log(formatted_string('00000000',123,''));
Output :
"0123"
"12300000"
Click me to see the solution.

21. Write a JavaScript function to repeat a string a specified times. Go to the editor
Test Data :
console.log(repeat_string('a', 4));
console.log(repeat_string('a'));
Output :
"aaaa"
"Error in string or count."
Click me to see the solution.

22. Write a JavaScript function to get a part of a string after a specified character.Go to the editor
Test Data :
console.log(subStrAfterChars('w3resource: JavaScript Exercises', ':','a'));
console.log(subStrAfterChars('w3resource: JavaScript Exercises', 'E','b'));
Output :
"w3resource"
"xercises"
Click me to see the solution.

23. Write a JavaScript function to strip leading and trailing spaces from a string. Go to the editor
Test Data :
console.log(strip('w3resource '));
console.log(strip(' w3resource'));
console.log(strip(' w3resource '));
Output :
"w3resource"
"w3resource"
"w3resource"
Click me to see the solution.

24. Write a JavaScript function to truncate a string to a certain number of words. Go to the editor
Test Data :
console.log(truncate('The quick brown fox jumps over the lazy dog', 4));
Output :
"The quick brown fox"
Click me to see the solution.

25. Write a JavaScript function to alphabetize a given string. Go to the editor
Alphabetize string : An individual string can be alphabetized. This rearranges the letters so they are sorted A to Z.
Test Data :
console.log(alphabetize_string('United States'));
Output :
"SUadeeinsttt"
Click me to see the solution.

26. Write a JavaScript function to remove the first occurrence of a given 'search string' from a string. Go to the editor
Test Data :
console.log(remove_first_occurrence("The quick brown fox jumps over the lazy dog", 'the'));
Output :
"The quick brown fox jumps over lazy dog"
Click me to see the solution.

27. Write a JavaScript function to convert ASCII to Hexadecimal format. Go to the editor
Test Data :
console.log(ascii_to_hexa('12'));
console.log(ascii_to_hexa('100'));
Output :
"3132"
"313030"
Click me to see the solution.

28. Write a JavaScript function to convert Hexadecimal to ASCII format. Go to the editor
Test Data :
console.log(hex_to_ascii('3132'));
console.log(hex_to_ascii('313030'));
Output :
"12"
"100"
Click me to see the solution.

29. Write a JavaScript function to find a word within a string. Go to the editor
Test Data :
console.log(search_word('The quick brown fox', 'fox'));
console.log(search_word('aa, bb, cc, dd, aa', 'aa'));
Output :
"'fox' was found 1 times."
"'aa' was found 2 times."
Click me to see the solution.

30. Write a JavaScript function check if a string ends with specified suffix. Go to the editor
Test Data :
console.log(string_endsWith('JS PHP PYTHON','PYTHON'));
true
console.log(string_endsWith('JS PHP PYTHON',''));
false
Click me to see the solution.

31. Write a JavaScript function to escapes special characters (&, <, >, ', ") for use in HTML. Go to the editor
Test Data :
console.log(escape_html('PHP & MySQL'));
"PHP &amp; MySQL"
console.log(escape_html('3 > 2'));
"3 &gt; 2"
Click me to see the solution.

32. Write a JavaScript function to remove?non-printable ASCII chars. Go to the editor
Test Data :
console.log(remove_non_ascii('???????PHP-MySQL??????'));
"PHP-MySQL"
Click me to see the solution.

33. Write a JavaScript function to remove non-word characters. Go to the editor
Test Data :
console.log(remove_non_word('PHP [email protected]#$%^&*()+`-={}[]|\\:";\'/?><., MySQL'));
"PHP - MySQL"
Click me to see the solution.

34. Write a JavaScript function to convert a string to title case. Go to the editor
Test Data :
console.log(sentenceCase('PHP exercises. python exercises.'));
"Php Exercises. Python Exercises."
Click me to see the solution.

35. Write a JavaScript function to remove HTML/XML tags from string. Go to the editor
Test Data :
console.log(strip_html_tags('<p><strong><em>PHP Exercises</em></strong></p>'));
"PHP Exercises"
Click me to see the solution.

36. Write a JavaScript function to create a Zerofilled value with optional +, - sign. Go to the editor
Test Data :
console.log(zeroFill(120, 5, '-'));
"+00120"
console.log(zeroFill(29, 4));
"0029"
Click me to see the solution.

37. Write a JavaScript function to test case insensitive (except special Unicode characters) string comparison. Go to the editor
Test Data :
console.log(compare_strings('abcd', 'AbcD'));
true
console.log(compare_strings('ABCD', 'Abce'));
false
Click me to see the solution.

38. Write a JavaScript function to create a case-insensitive search. Go to the editor
Test Data :
console.log(case_insensitive_search('JavaScript Exercises', 'exercises'));
"Matched"
console.log(case_insensitive_search('JavaScript Exercises', 'Exercises'));
"Matched"
console.log(case_insensitive_search('JavaScript Exercises', 'Exercisess'));
"Not Matched"
Click me to see the solution.

39. Write a JavaScript function to Uncapitalize? the first character of a string. Go to the editor
Test Data :
console.log(Uncapitalize('Js string exercises'));
"js string exercises"
Click me to see the solution.

40. Write a JavaScript function to Uncapitalize the first letter of each word of a string. Go to the editor
Test Data :
console.log(unCapitalize_Words('Js String Exercises'));
"js string exercises"
Click me to see the solution.

41. Write a JavaScript function to capitalize each word in the string. Go to the editor
Test Data :
console.log(capitalizeWords('js string exercises'));
"JS STRING EXERCISES"
Click me to see the solution.

42. Write a JavaScript function to uncapitalize each word in the string. Go to the editor
Test Data :
console.log(unCapitalizeWords('JS STRING EXERCISES'));
"js string exercises"
Click me to see the solution.

43. Write a JavaScript function to test whether the character at the provided (character) index is upper case. Go to the editor
Test Data :
console.log(isUpperCaseAt('Js STRING EXERCISES', 1));
false
Click me to see the solution.

44. Write a JavaScript function to test whether the character at the provided (character) index is lower case. Go to the editor
Test Data :
console.log(isLowerCaseAt ('Js STRING EXERCISES', 1));
true
Click me to see the solution.

45. Write a JavaScript function to get humanized number with the correct suffix such as 1st, 2nd, 3rd or 4th. Go to the editor
Test Data :
console.log(humanize(1));
console.log(humanize(20));
console.log(humanize(302));
"1st"
"20th"
"302nd"
Click me to see the solution.

46. Write a JavaScript function to test whether a string starts with a specified string. Go to the editor
Test Data :
console.log(startsWith('js string exercises', 'js'));
true
Click me to see the solution.

47. Write a JavaScript function to test whether a string ends with a specified string. Go to the editor
Test Data :
console.log(endsWith('JS string exercises', 'exercises'));
true
Click me to see the solution.

48. Write a JavaScript function to get the successor of a string. Go to the editor

Note: The successor is calculated by incrementing characters starting from the rightmost alphanumeric (or the rightmost character if there are no alphanumerics) in the string. Incrementing a digit always results in another digit, and incrementing a letter results in another letter of the same case. If the increment generates a carry, the character to the left of it is incremented. This process repeats until there is no carry, adding an additional character if necessary.
Example :
string.successor("abcd") == "abce"
string.successor("THX1138") == "THX1139"
string.successor("< >") == "< >"
string.successor("1999zzz") == "2000aaa"
string.successor("ZZZ9999") == "AAAA0000"

Test Data :
console.log(successor('abcd'));
console.log(successor('3456'));
"abce"
"3457"
Click me to see the solution.

49. Write a JavaScript function to get unique guid (an acronym for 'Globally Unique Identifier?) of the specified length, or 32 by default. Go to the editor
Test Data :
console.log(guid());
console.log(guid(15));
"hRYilcoV7ajokxsYFl1dba41AyE0rUQR"
"b7pwBqrZwqaDrex"
Click me to see the solution.

More to Come !

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JavaScript: Tips of the Day

JavaScript: Updates the values of the properties

const user = {
	email: "[email protected]",
	password: "12345"
}

const updateUser = ({ email, password }) => {
	if (email) {
		Object.assign(user, { email })
	}

	if (password) {
		user.password = password
	}

	return user
}

const updatedUser = updateUser({ email: "[email protected]" })

console.log(updatedUser === user)

The updateUser function updates the values of the email and password properties on user, if their values are passed to the function, after which the function returns the user object. The returned value of the updateUser function is the user object, which means that the value of updatedUser is a reference to the same user object that user points to. updatedUser === user equals true.

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