All JavaScript Strings Methods ( Cheatsheet )

length: Returns the length of a string. Example: "Hello".length returns 5.

charAt(index): Returns the character at the specified index in a string. Example: "Hello".charAt(1) returns "e".

concat(str1, str2, ...): Combines two or more strings and returns a new string. Example: "Hello".concat(" ", "world!") returns "Hello world!".

toUpperCase(): Converts a string to uppercase. Example: "hello".toUpperCase() returns "HELLO".

toLowerCase(): Converts a string to lowercase. Example: "HELLO".toLowerCase() returns "hello".

trim(): Removes whitespace from both ends of a string. Example: " Hello ".trim() returns "Hello".

split(separator, limit): Splits a string into an array of substrings based on a specified separator. Example: "Hello,world".split(",") returns ["Hello", "world"].

indexOf(searchValue, startIndex): Returns the index of the first occurrence of a specified value in a string. Example: "Hello".indexOf("o") returns 4.

replace(searchValue, newValue): Replaces a specified value with another value in a string. Example: "Hello".replace("o", "i") returns "Helli".

substring(startIndex, endIndex): Returns a substring based on the specified start and end index. Example: "Hello".substring(1, 4) returns "ell".

slice(startIndex, endIndex): Returns a portion of a string starting from the specified start index to the specified end index. Example: "Hello".slice(1, 4) returns "ell".

startsWith(searchString): Checks if a string starts with the specified search string and returns a boolean value. Example: "Hello".startsWith("H") returns true.

endsWith(searchString): Checks if a string ends with the specified search string and returns a boolean value. Example: "Hello".endsWith("o") returns true.

includes(searchString): Checks if a string contains the specified search string and returns a boolean value. Example: "Hello".includes("ell") returns true.