Six-way JavaScript quiz questions

1. Find the largest element in a numeric array (using the Match.max function)

1 var a=[123,23432,345,3,34]; 2 console.log (Math.max.apply (null, a));

2. Convert a numeric array into a function array (each function pops up the corresponding number)

1 var a=[123,23432,345,3,34]; 2 a=a.map (function(value) {3     returnfunction() {  4        alert (value); 5     }; 6 }); 7 Console.log (A[3] ());

3. Sort an object array (sorting criteria is the number of attributes per element object)

varArr=[{A:1,b:2,c:3}, {a:1,b:2,c:3,d:4,e:5}, {a:1,b:2}, {a:1,b:2,c:3,d:4}];object.prototype.proplength=(Object.prototype.hasOwnProperty (' _count_ ')?function (){        return  This. _count_;//FF    }    :    function(){    varP,count=0;  for(pinch  This){        if( This. hasOwnProperty (P)) {Count++; }    }    returncount;});functionCompare (obj1,obj2) {returnObj1.proplength ()-obj2.proplength ();} Console.log (Arr.sort (Compare));

4. Use JavaScript to print out the number of Fibonacci (without using global variables)

1 function Fibo (n) {2      var self=Arguments.callee; 3      if (n<2) {4          return N; 5      }6      return self (n-1) +self (n-2); 7 }8  Console.log (Fibo (6));

5, to achieve the following syntax functions: var a = (5). Plus (3). Minus (6); 2

1number.prototype.plus=function(a) {2     return  This. ValueOf () +A;3 };4number.prototype.minus=function(a) {5     return  This. ValueOf ()-A;6 };7 varA = (5). Plus (3). Minus (6);8Console.log (a);

6, to achieve the following syntax function: var a = Add (2) (3) (4); 9

The answer comes from the Gaubee in-depth understanding of the JavaScript series (20): Do you really understand JavaScript? Answer in a detailed answer.

1 functionAdd (num) {2     varself=Arguments.callee;3num+=~~Self ;4self.num=num;5     returnSelf ;6 }7 //valueof is for operation and console use, ToString is for alert8add.valueof=add.tostring=function(){returnAdd.num;};9 varA = Add (2) (3) (4);TenConsole.log (a);

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Six-way JavaScript quiz questions