list of the most common JavaScript string methods

Nozibul Islam - Nov 5 - - Dev Community

list of the most common JavaScript string methods:

  • length:
let message = "Hello, world!";
console.log(message.length); // Output: 13
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  • concat():
let greeting = "Hello";
let name = "Alice";
let fullGreeting = greeting.concat(", ", name, "!");
console.log(fullGreeting); // Output: "Hello, Alice!"
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  • charAt():
let message = "JavaScript";
console.log(message.charAt(0)); // Output: "J"
console.log(message.charAt(5)); // Output: "S"
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  • indexOf():
let sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.indexOf("quick")); // Output: 4
console.log(sentence.indexOf("dog")); // Output: 37
console.log(sentence.indexOf("lion")); // Output: -1 (not found)
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  • lastIndexOf():
let quote = "To be, or not to be, that is the question.";
console.log(quote.lastIndexOf("be")); // Output: 23
console.log(quote.lastIndexOf("the")); // Output: 33
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  • slice():
let fruit = "apple, banana, cherry";
console.log(fruit.slice(0, 5)); // Output: "apple"
console.log(fruit.slice(7, 13)); // Output: "banana"
console.log(fruit.slice(15)); // Output: "cherry"
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  • substring():
let text = "Hello, world!";
console.log(text.substring(0, 5)); // Output: "Hello"
console.log(text.substring(7, 12)); // Output: "world"
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  • substr():
let message = "The quick brown fox jumps.";
console.log(message.substr(4, 5)); // Output: "quick"
console.log(message.substr(10)); // Output: "brown fox jumps."
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  • toLowerCase():
let text = "JAVASCRIPT IS AWESOME!";
console.log(text.toLowerCase()); // Output: "javascript is awesome!"
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  • toUpperCase():
let text = "hello, world!";
console.log(text.toUpperCase()); // Output: "HELLO, WORLD!"
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  • trim():
let greeting = "   Hello, world!   ";
console.log(greeting.trim()); // Output: "Hello, world!"
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  • replace():
let text = "I like cats. Cats are fluffy.";
console.log(text.replace("cats", "dogs")); // Output: "I like dogs. Cats are fluffy."
console.log(text.replace(/cats/i, "dogs")); // Output: "I like dogs. Cats are fluffy." (case-insensitive)
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  • split():
let csv = "apple,banana,cherry";
let fruits = csv.split(",");
console.log(fruits); // Output: ["apple", "banana", "cherry"]
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  • includes():
let message = "The quick brown fox jumps over the lazy dog.";
console.log(message.includes("quick")); // Output: true
console.log(message.includes("tiger")); // Output: false
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  • startsWith():
let greeting = "Hello, world!";
console.log(greeting.startsWith("Hello")); // Output: true
console.log(greeting.startsWith("world")); // Output: false
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  • endsWith():
let filename = "myfile.pdf";
console.log(filename.endsWith(".pdf")); // Output: true
console.log(filename.endsWith(".txt")); // Output: false
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  • match():
let text = "The quick brown fox jumps.";
let pattern = /quick/;
console.log(text.match(pattern)); // Output: ["quick"]
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  • search():
let text = "The quick brown fox jumps.";
let pattern = /brown/;
console.log(text.search(pattern)); // Output: 10
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  • repeat():
let message = "Hello ";
console.log(message.repeat(3)); // Output: "Hello Hello Hello "
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  • trimStart():
let greeting = "   Hello, world!   ";
console.log(greeting.trimStart()); // Output: "Hello, world!   "
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  • trimEnd():
let greeting = "   Hello, world!   ";
console.log(greeting.trimEnd()); // Output: "   Hello, world!"
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  • padStart():
let number = "42";
console.log(number.padStart(4, "0")); // Output: "0042"
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  • padEnd():
    let word = "JavaScript";
    console.log(word.padEnd(15, ".")); // Output: "JavaScript....."

  • splice():

let str = "Hello, world!";
let result = str.splice(7, 5, "everyone");
console.log(result); // Output: "world"
console.log(str); // Output: "Hello, everyone!"
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  • toString():
let num = 42;
console.log(num.toString()); // Output: "42"
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  • valueOf():
let str = "JavaScript";
console.log(str.valueOf()); // Output: "JavaScript"
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  • charCodeAt():
let message = "Hello";
console.log(message.charCodeAt(0)); // Output: 72
console.log(message.charCodeAt(4)); // Output: 111
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  • codePointAt():
let emoji = "😀";
console.log(emoji.codePointAt(0)); // Output: 128512
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normalize():

let str1 = "café";
let str2 = "cafe\u0301";
console.log(str1.normalize() === str2.normalize()); // Output: true
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This covers a wide range of string manipulation tasks in JavaScript, from basic operations like getting the length or concatenating strings to more advanced techniques like pattern matching and Unicode normalization.

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