Strings are a sequence of zero or more characters written inside quotes used to represent text.
Strings may consist of letters, numbers, symbols, words, or sentences.
Strings are immutable, they cannot be changed.
Each character in a string has an index.
The first character will be index 0 the second character will be index 1 and so on.
There are two ways to access an individual character in a string.
charAt() method
const str1 = "abc"; string
str1.charAt(0); character at index 0 → "a"
str1.charAt(1); character at index 1 → "b"
str1.charAt(2); character at index 2 → "c"
str1.charAt(3); character at index 3 → "" index not found
Alternatively use at() or slice() methods
bracket notation []
const str2 = "abc"; string
str2[0]; character at index 0 → "a"
str2[1]; character at index 1 → "b"
str2[2]; character at index 2 → "c"
str2[3]; character at index 3 → undefined index not found
Numbers are used to represent both integer and floating-point values.
Numbers are most commonly expressed in literal forms like 255 or 3.14159 ↴
let num1 = 5; → number
let num2 = 2.5; → number
let num3 = num1 + num2;
console.log(num3); returns ↴
7.5 → number
Repeat a string using the built-in repeat method ↴
repeat() method returns a new string which contains the specified number of copies of this string, concatenated together.
syntax
string.repeat(count)
Repeat string "Hello" 3 times.
const str = "Hello"; → string
const count = 3; → number of times to repeat the string
str.repeat(3); returns ↴
"HelloHelloHello" → string repeated 3 times
RangeError thrown if count is negative or if count overflows maximum string length.
Initialize a variable to hold the string to repeat.
const string1 = "All work and no play!" → user input
Initialize a variable to hold the number of times to repeat the string.
const number1 = 3 → user input
Define a function repeatString() to repeat a string n times.
function repeatString(str, num) {}
The function takes a string str and a number num and returns a new string that consists of the original string repeated num times. The original string is unchanged.
Use the repeat method to create a new string.
return str.repeat(num)
Call the function with ↴
repeatString(string1, number1);
Repeat a string 3 times.
const string1 = "All work and no play!";
const number1 = 3;
function repeatString(str, num) {
return str.repeat(num);
}
call function
repeatString(string1, number1); returns ↴
"All work and no play!All work and no play!All work and no play!"
Returns RangeError if num less than 0
Alternative to prevent RangeError if num is negative ↴
Repeat a string -3 times.
const string2 = "All work and no play!";
const number2 = -3; → negative num
function repeatString2(str, num) {
return num > 0 ? str.repeat(num) : "";
}
repeatString2(string2, number2); returns ↴
""