JS Strings

Question 1

.charAt(index)

str.charAt(0);

Answer 1

returns character at specified index

Question 2

.charCodeAt(index)

str.charCodeAt(0);

Answer 2

returns unicode of character at specified index

Question 3

.concat(str, ?…)

str1.concat(str2, str3, …);

Answer 3

joins 2+ strings and returns one string

Question 4

.endsWith(searchvalue, ?length)
default length is string length

str.endsWith(“bye.”);

Answer 4

returns boolean, checks whether string ends with specified characters (case-sensitive)

Question 5

String.fromCharCode(char_code,…)

String.fromCharCode(72, 69, 76, 76, 79);

Answer 5

converts a unicode number to a character

Question 6

.includes(searchvalue, ?startindex)

str.includes(“world”);

Answer 6

returns boolean whether string includes specified string

Question 7

.indexOf(searchvalue, ?start)

str.indexOf(“world”);

Answer 7

returns index of first occurrence of search value in string, returns -1 if no value found

Question 8

.lastIndexOf(searchvalue, ?start)

str.lastIndexOf(“world”);

Answer 8

returns index of last occurrence of search value in string, returns -1 if no value found

Question 9

.localCompare(comparestring)

str1.localCompare(str2);

Answer 9

compares two string in the current locale, returns -1,0,1 depending on sort order comparing; -1 reference sorts before compare string…

Question 10

.match(regex)

str.match(/rain/i);

Answer 10

returns an array of values matching the regex

Question 11

.repeat(number)

str.repeat(2)

Answer 11

returns a new string with set number of duplicates of reference string

Question 12

.replace(searchvalue,newvalue)

str.replace(/blue/g, “red”);

Answer 12

returns new string replacing search value (string or regex) with new value

Question 13

.search(searchvalue)

str.search(“world”);

Answer 13

returns a Number, representing the position of the first occurrence of the specified searchvalue, or -1 if no match is found

Question 14

string.slice(start, ?end)

str. slice(1, 5); (incl 1, excl 5)
str. slice(0) extracts whole string
str. slice(-1) extracts last character

Answer 14

returns a String, representing the extracted part of the string.

Question 15

string.split(separator, ?limit)

str.split(“ “);
str.split(“”) splits every value
limit cuts off array after set number of items

Answer 15

returns an Array, containing the splitted values

Question 16

string. startsWith(searchvalue, ?start)

str. startsWith(“Hello”);

Answer 16

Returns true if the string starts with the value, otherwise it returns false

Question 17

string.substr(start, ?length)

str.substr(2);
returns remainder of string if no length
If length is 0 or negative, an empty string is returned.
if start negative then from end of string

Answer 17

Returns a new String, containing the extracted part of the text.

Question 18

string.substring(start, ?end)

if start negative then defaults to zero

Answer 18

returns a new String containing the extracted characters

Question 19

string.toLowerCase()

Answer 19

returns a String, representing the value of a string converted to lowercase

Question 20

string.toString()

Answer 20

returns a String, representing the value of a string

Question 21

string.toUpperCase()

Answer 21

returns a String, representing the value of a string converted to uppercase

Question 22

string.trim()

Answer 22

returns a String, representing the string with removed whitespace from both ends

Question 23

string.valueOf()

not usually called

Answer 23

returns a String, representing the primitive value of a string