Скачать или смотреть JAVASCRIPT STRING CHEAT SHEET| QA SDET

🔤 String Declaration

let str1 = "Hello";
let str2 = 'World';
let str3 = `Hello, ${str2}`; // Template literal


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📏 Length

str.length // Number of characters


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🔍 Search / Check

str.includes("lo"); // true
str.startsWith("He"); // true
str.endsWith("lo"); // true
str.indexOf("l"); // 2
str.lastIndexOf("l"); // 3


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✂️ Slice / Substring

str.slice(0, 3); // "Hel"
str.substring(0, 3); // "Hel"
str.substr(0, 3); // "Hel" (deprecated)


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🔧 Modify

str.toUpperCase(); // "HELLO"
str.toLowerCase(); // "hello"
str.trim(); // Removes leading/trailing spaces
str.replace("lo", "y"); // "Hey"
str.repeat(2); // "HelloHello"


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🧩 Split & Join

str.split(" "); // ["Hello", "World"]
arr.join("-"); // "Hello-World"


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🪜 Character Access

str.charAt(1); // "e"
str[1]; // "e"
str.charCodeAt(1); // 101 (ASCII)


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🔗 Concatenation

str1 + str2 // "HelloWorld"
str1.concat(str2); // "HelloWorld"


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🧪 Compare

str1 === str2 // Strict compare
str1.localeCompare(str2) // -1, 0, 1


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🧵 Multiline & Escape

let msg = `Line1
Line2`; // Multiline with backticks

let quote = "She said \"hi\""; // Escape quote