JS String

Question 1

What is log?
let name = ‘John’
let message = Hello ${name}
console.log(message);

Answer 1

Hello John

Question 2

What is log?
let str = ‘I'm a string’
console.log(str.length);

Answer 2

12

Question 3

What is log?
let str = ‘I'm a string’
console.log(str[7]);

Answer 3

t

Question 4

What is log?
let str = ‘I'm a string’
console.log(str[str.length-1]);

Answer 4

g

Question 5

What is log?
let className = ‘btn’
className += ‘ btn-primary’
className += ‘ none’
console.log(className);

Answer 5

btn btn-primary none

Question 6

What is JS string

Answer 6

JS string are primitive values and immutable
Litteral string delimited by ‘ quotes, double quotes “ , backticks ~

Question 7

Find the length of a string

Answer 7

let str = ‘I'm a string’
console.log(str.length);

Question 8

How to compare 2 strings?

Answer 8

Use <,<=, >,>=, ==

Question 9

How to get value of string?

Answer 9

Whit methods of the string objects:
valueOf()
toString()
toLocaleString()

Question 10

How to find the character of position?

Answer 10

console.log(str.charAt(1))

Question 11

Which method is used, what is the output?

let nameN = ‘Lia’
let fullName =nameN.concat(“ “,’LiaN’)
console.log(fullName);

let arr = [‘One’, ‘Two’, ‘Three’]
console.log(‘‘.concat(arr));

Answer 11

Concatenation for String
Lia LiaN

One,Two,Three

Question 12

Which method is used, what is the output?

let strN = ‘JavaScript String’
console.log(strN.substr(0,10));
console.log(strN.substr(11,6));

Answer 12

Extracting substrings whit substr() /1 - start index 2- lenght of the number of chracters for extrating

JavaScript
String

Question 13

Which method is used, what is the output?
let strS = ‘JavaScript String’
console.log(strS.substring(2,6));

Answer 13

Extracting substrings whit substring() /1 - start index 2- end index for extrating
vaSc

Question 14

Which method is used, what is the output?
let strSS = ‘JavaScript String String’
console.log(strSS.indexOf(‘St’));
console.log(strSS.indexOf(‘St’, 12));

Answer 14

Locating substrings whit indexOf() - is case-sensitive
1 - substring to locate first occurence 2- index at which searching in string
if searching index dont’t exist output is -1
11
18

Question 15

Which method is used, what is the output?
let strSS1 = ‘ JavaScript String String ‘
console.log(strSS1.trimStart());
console.log(strSS1.trimEnd());

Answer 15

Removing the space whit trimStart() for start
whit trimEnd() for end
trim() remove space from end and start
‘JavaScript String String ‘
‘ JavaScript String String’

Question 16

Which method is used, what is the output?

let strSS2 = ‘ JavaScript String String ‘
console.log(strSS2.toUpperCase());
console.log(strSS2.toLowerCase());

Answer 16

Changing letters
toUpperCase()
JAVASCRIPT STRING STRING
.toLowerCase()
javascript string string

Question 17

Which method is used, what is the output?
let strSS3 = ‘JavaScript String String’
console.log(strSS3.search(/St/));

Answer 17

search() the position of first matching
11

Question 18

Which method is used, what is the output?
let strSS4 = ‘JavaScript String String’
console.log(strSS4.replace(‘JavaScript’, ‘JS’));

Answer 18

replace()
replace str whit new str
JS String String

Question 19

Which method is used, what is the output?

let strSS5 = ‘JavaScript String String’
console.log(strSS5.split(‘ ‘));
console.log(strSS5.split(‘ ‘,2));

Answer 19

split() - to devide str into arr of strings by separator , second parameter is for return limited number of splits
[ ‘JavaScript’, ‘String’, ‘String’ ]
[ ‘JavaScript’, ‘String’ ]

Question 20

Which method is used, what is the output?
let strSS6 = ‘JavaScript@mail.com’
console.log(strSS6.slice(0,strSS6.indexOf(‘@’)));

Answer 20

slice() - extract a string from a string
JavaScript

Question 21

Which method is used, what is the output?

let strSS7 = ‘JavaScript@mail.com’
console.log(strSS7.includes(‘@’));

Answer 21

includes() determinate is string contains whit another string

true