Front-End written questions: Beat the multidimensional array, extract the parameters in the URL into an object, implement the trim () function of a string, determine the email address, 16 binary color to RGB format

(1) Flat array

This is a well-known internet company today's front-end written questions: multidimensional array dimension variable, such as [2,4,1,[2,3,4,[1,2],5,3],3,8] beat flat for [2,4,1,2,3,4,1,2,5,3,3,8]. The number of dimensions is variable and should be recursive:

Answer:

function flatten(arr){var arrLength=arr.length;fori=0;i<arrLength;i++){    if(arr[i].constructor==Array){        arr.splice(i,1,flatten(arr[i]));    }}return arr;}

(2) Extract the parameters from the URL into an object

This is also an internet company's front-end pen test, with Memory records,
A URL such as "http://www.taobao.com/index.php?key0=0&key1=1&key2=2 ..." Extract parameters, Output:
{
key0:0,
Key1:1,
Key2:2,
...
}

Answer:

function  parsequerystring   (ustring)  { ustring= Ustring.slice (Ustring.indexof () +1 ); var  arr=ustring.split ( "&" ); var  result=new   Object  (); for  (var  i=0 ; i<arr.length;i++) {var  kv=arr[i]; Kvarray=kv.split ( "=" ); Result[kvarray[0 ]]=kvarray[1 ]; } return  result} 

(3) The use of JS code to achieve the removal before and after the string before and after the white space trim () function

Line such as "abc" = = "abc" "ABC" ==> "ABC"

Answer:

    String.prototype.trim=function(){       var result=this.replace(/^\s+|\s+$/g,"");        return result;    }

(4) Implement a function to determine if it is the correct email address

The problem is the use of Kauzheng expression, email address such as [email protected]
So the notation should be/^ ([a-za-z0-9_.-]) +\@ ([a-za-z0-9-]) +.) + ([a-za-z0-9]{2,4}) $/

Answer:

function checkEmailAddress(address){    if(/^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})$/.test(address)){        returntrue    }else{        returnfalse    }}

(5) 16 binary colors to RGB format: requirements: #0000ff = = RGB (0,0,255)

Invalid=>invalid
#G00 ==> #G00

Answer:

varParsecolor = function(val){      varR, G, B;//parameter is RGB mode, do not make a binary conversion, directly intercept the string can     if(/rgb/. Test (val)) {vararr = Val.match (/\d+/g); R =parseint(arr[0] ); g =parseint(arr[1] ); b =parseint(arr[2] ); }///parameter is 16 binary requires a binary conversion     Else if(/#/. Test (val)) {varlen = val.length;//Non-abbreviated mode #0066cc         if(len = =7) {r =parseint(Val.slice (1,3), -); g =parseint(Val.slice (3,5), -); b =parseint(Val.slice (5), -); }Else if(len==4){returnVal }     }Else{returnVal }return the RGB ("+r+","+g+","+b+")"; };

Front-End written questions: Beat the multidimensional array, extract the parameters in the URL into an object, implement the trim () function of a string, determine the email address, 16 binary color to RGB format