Strings (Real Patterns)

20 Exercises Available

trim, normalize, search, slug — commonly used in UI/content.

Slugify (URL-friendly)

Create a function `slugify(text)`. Rules: lowercase, trim, spaces → dash, remove non-alphanumeric, collapse multiple dashes.

Sample Output:

slugify("Hello World!") => "hello-world"
slugify("  My First Post  ") => "my-first-post"

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2.Easy

Mask Phone Number

Function `maskPhone(phone)` banao jo last 4 digits visible रखे, बाकी `*`. Example: "9876543210" → "******3210"

Sample Output:

maskPhone("9876543210") => "******3210"
maskPhone("+91-98765-43210") => "******3210"

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3.Easy

Count Words (robust)

Create a function `wordCount(text)` that handles multiple spaces/newlines and returns word count.

Sample Output:

wordCount("Hello World") => 2
wordCount("  Multiple   Spaces  ") => 2
wordCount("") => 0

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4.Easy

Case-insensitive Includes

Create a function `includesCI(text, query)` (case-insensitive).

Sample Output:

includesCI("Hello World", "hello") => true
includesCI("JavaScript", "SCRIPT") => true
includesCI("Python", "java") => false

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5.Medium

Extract Domain from URL

Create a function `getDomain(url)`. Return null for invalid URL.

Sample Output:

getDomain("https://google.com/search") => "google.com"
getDomain("http://example.com") => "example.com"
getDomain("invalid-url") => null

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6.Easy

Capitalize First Letter of Each Word

Create a function `titleCase(str)` that capitalizes first letter of each word in string. Example: titleCase("hello world") => "Hello World"

Sample Output:

titleCase("hello world") => "Hello World"
titleCase("JAVASCRIPT IS FUN") => "Javascript Is Fun"

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7.Easy

Remove All Whitespace

Function `removeWhitespace(str)` banao jo string se sabhi whitespace characters remove kare. Example: removeWhitespace("hello world") => "helloworld"

Sample Output:

removeWhitespace("hello world") => "helloworld"
removeWhitespace("  a  b  c  ") => "abc"

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8.Easy

Check if String Ends with Suffix

Function `endsWith(str, suffix)` banao jo check kare ki string suffix se end hoti hai ya nahi (case-insensitive). Example: endsWith("hello.js", ".js") => true

Sample Output:

endsWith("hello.js", ".js") => true
endsWith("file.TXT", ".txt") => true
endsWith("test", ".js") => false

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9.Easy

Extract Numbers from String

Function `extractNumbers(str)` banao jo string se sabhi numbers extract kare. Example: extractNumbers("abc123def456") => [123, 456]

Sample Output:

extractNumbers("abc123def456") => [123, 456]
extractNumbers("price: $100") => [100]

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10.Easy

Reverse String (preserve spaces)

Function `reverseString(str)` banao jo string ko reverse kare but spaces ko preserve kare. Example: reverseString("hello world") => "dlrow olleh"

Sample Output:

reverseString("hello") => "olleh"
reverseString("hello world") => "dlrow olleh"

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11.Easy

Check if String Contains Only Letters

Function `isAlpha(str)` banao jo check kare ki string me sirf letters hain (a-z, A-Z). Example: isAlpha("Hello") => true, isAlpha("Hello123") => false

Sample Output:

isAlpha("Hello") => true
isAlpha("Hello123") => false
isAlpha("") => false

View Solution

12.Easy

Truncate String with Ellipsis

Function `truncate(str, maxLength)` banao jo string ko truncate kare aur ellipsis add kare. Example: truncate("Hello world", 8) => "Hello..."

Sample Output:

truncate("Hello world", 8) => "Hello..."
truncate("Short", 10) => "Short"

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13.Easy

Count Occurrences of Substring

Function `countOccurrences(str, substr)` banao jo string me substring ki count return kare. Example: countOccurrences("hello hello", "hello") => 2

Sample Output:

countOccurrences("hello hello", "hello") => 2
countOccurrences("aaa", "aa") => 2

View Solution

14.Easy

Remove Duplicate Characters

Function `removeDuplicates(str)` banao jo string se duplicate characters remove kare. Example: removeDuplicates("hello") => "helo"

Sample Output:

removeDuplicates("hello") => "helo"
removeDuplicates("aabbcc") => "abc"

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15.Medium

Check if String is Valid URL

Function `isValidURL(str)` banao jo check kare ki string valid URL hai ya nahi. Example: isValidURL("https://example.com") => true

Sample Output:

isValidURL("https://example.com") => true
isValidURL("not-a-url") => false

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16.Easy

Pad String to Fixed Width

Function `pad(str, width, char=" ", side="right")` banao jo string ko specified width tak pad kare. Example: pad("hello", 10, " ", "right") => "hello "

Sample Output:

pad("hello", 10) => "hello     "
pad("hello", 10, " ", "left") => "     hello"

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17.Medium

Find Longest Common Prefix

Function `longestCommonPrefix(strs)` banao jo array of strings me longest common prefix find kare. Example: longestCommonPrefix(["flower", "flow", "flight"]) => "fl"

Sample Output:

longestCommonPrefix(["flower", "flow", "flight"]) => "fl"
longestCommonPrefix(["dog", "cat"]) => ""

View Solution

18.Medium

Convert CamelCase to kebab-case

Function `camelToKebab(str)` banao jo camelCase string ko kebab-case me convert kare. Example: camelToKebab("helloWorld") => "hello-world"

Sample Output:

camelToKebab("helloWorld") => "hello-world"
camelToKebab("myVariableName") => "my-variable-name"

View Solution

19.Easy

Check if String is Anagram

Function `isAnagram(str1, str2)` banao jo check kare ki dono strings anagram hain ya nahi. Example: isAnagram("listen", "silent") => true

Sample Output:

isAnagram("listen", "silent") => true
isAnagram("hello", "world") => false

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20.Medium

Extract Query Parameters from URL

Function `getQueryParams(url)` banao jo URL se query parameters extract kare. Example: getQueryParams("https://example.com?name=John&age=30") => {name: "John", age: "30"}

Sample Output:

getQueryParams("https://example.com?name=John&age=30") => {name: "John", age: "30"}
getQueryParams("https://example.com") => {}

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