Object, Array, String: Methods

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• Object methods
• Array methods
• String methods

Object methods

delete()

• removes the property of an object
• returns bolean

assign()

• makes copy of values from one or more source objects to a target object
• returns target object

Array methods

Array: search, select

filter()

• finds all elements matching query; query can be a function returning bolean
• makes new array from the result of callback function, if negative new array is empty; does not change the original array

map()

• calls a function for all elements of an array
• makes new array from the result of callback function; does not change the original array

includes()

• finds if searched element is in an array
• returns bolean

find()

• finds the first element matching query
• returns it or undefined if not found

findIndex()

• finds the first element matching query
• returns its index or -1 if not found

indexOf()

• finds if searched element is in an array
• returns its index or -1 if not found

lastIndexOf()

• the same as indexOf but starts from the end

some()

• find if any element matches request
• returns bolean

every()

• find if every elements match request
• returns bolean

Array: change

join()

• joins the elements of an array into a string; argument is a separator
• returns string

reduce()

• reduces values of all array elements to a single value kept in accumulator
• reducer function

reduceRight()

• the same as reduce() but starts from the end

reverse()

• reverses the order of all elements of an array

sort()

• sorts the elements of an array
• changes the original array

Array: add, remove

shift()

• removes the first element of an array
• returns it

pop()

• removes the last element of an array
• returns it

unshift()

• adds a new element at the beginning
• returns lenght of an array

push()

• adds a new element at the end of an array
• returns lenght of an array

slice()

• selects a part of an array specified by beginning and end of splice or all array if end is not specified
• returns the new array
• does not change the original array; both parameters are optional: start (from where to select), and end (index where to stop; index element is not taken), defaults are zero and the end

splice()

• adds/removes elements from an array specified by beginning and end of splice, if beginning is negative it operates at the end of an array; end is specified by number of elements to delete, if 0 it just place new element into an array
• returns removed elements
• changes the original array; index (from what point to change) is obligatory, end (how many elements to delete) and elements are optional

String methods

charAt()

• finds the character at the specified index (starts with 0, -1 is the last one) in a string
• returns it

concat()

• joins two or more strings, those after first are passed as an arguments; does ot change them
• returns new concatenated string

includes()

• checks if the calling string contains a string passed as an argument; case sensitive
• returns bolean

endsWith()

• checks if the calling string ends with a string passed as an argument; case sensitive
• returns bolean

indexOf()

• finds first ocurence of a specified argument; optional second argument is an integer specifying index of place where to start searching; case sensitive
• returns index, or -1 if not found

lastIndexOf()

• the same as indexOf(), but backwards

match()

• searches a string for a match against a regular expression; without g modifier (global) it finds only the first one
• returns the matches (as substring), index, and the input, all as an Array object, or null if not found

repeat()

• finds an element at index given as an argument
• returns a string of that element repeated number of times (this number is a second argument), or empty string if no argument or argument 0

replace()

• finds a match between a regular expression (or a specified value) and a string; does not change the original string; without g modifier (global) it replaces only the first occurence
• returns a new string where the specified values are replaced, or the original string if no match is found

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search()

• searches for a match between a string or regular expression and a specified string
• returns the index of the first character of the first match, or -1 if no match is found

slice()

• extracts a section of a string, from the index specified in the first argument, to index specified by the second argument (i, j-1), or end of string if there's no second argument; negative numbers are extracting from the end
• returns result, or the entire string if no arguments are passed, as a new string

split()

• splits a string into an array of strings by separating the string into substrings, argument is the separator; does not change the original string
• returns an array of substrings, or the entire array of string's elements if no argument or empty argument ('') are passed

startsWith()

• checks if a string begins with a string passed as an argument; case sensitive
• returns bolean

substr()

• extracts strings of number of characters specified in the second argument from index specified in the first argument; negative number extracts from the end of a string; does not change the original string
• returns a substring of elements at a given range

substring()

• extracts strings form index specified in the first argument to index specified in the second argument; does not change the original string
• returns a substring of elements at a given range

toLowerCase()

• does not change the original string
• returns the calling string converted to lowercase letters

toUpperCase()

• does not change the original string
• returns the calling string converted to uppercase letters

trim()

• removing whitespaces from both ends of string; does not change the original string
• returns changed string

trimLeft()

• removing whitespace from the left side
• returns changed string

trimRight()

• removing whitespace from the right side
• returns changed string

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