javascript technical interview questions

The requirements for JavaScript developers in the IT community are still high, but if JavaScript developers have the skills and experience to reach a certain level, they can easily jump to a good company, and of course the salary is not a problem. But before the interview, the interview preparation should be sufficient

First, things begin with a question simple ; a2.name=xxx; A1.name will become str2=str1; str2=xxx; STR1 won't change. Welcome to think nonsense too many students go straight to the end to see "technical flow explanation" ha, then we start Apply a more Vulgar words: "I know the truth, but why the string will not change it", JavaScript as a high-level language does not have the concept of point

The requirements for JavaScript developers in the IT community are still high, but if JavaScript developers have the skills and experience to reach a certain level, they can easily jump to a good company, and of course the salary is not a problem. But before the interview, the interview preparation should be sufficient

I do not know my JS level how, but today a bit hit, see a lot of problems have pits. After reading some interview questions, I recorded the pits I met today.Issue 1: ScopeConsider the following code, what is the output?(functionvar a = b = 5;}) (); Console.log (b);The answer is 5.The problem I know, the trap is that var a = b = 5, if it is a declaration, it should be Var, a, B = 5, so the value of a, B is 5

" because it is the first sentence of the function and does not use a setTimeout() function to delay it. Then output "4" because it is not delayed by the number and is not queued. Then, the remaining "2", "3", both are queued, but the former needs to wait a second, the latter waiting for 0 seconds (which means that the engine completes the first two outputs immediately after the completion of the). This explains why "3" precedes "2".Issue 10: AlgorithmWrites a isPrime() function that returns whe

passing it on === .5. Array is not the underlying typetypeof // true typeof // true typeof // true // but ..... typeof // trueIf you want to determine var whether a variable is an array, you need to use Array.isarray (var) .6. ClosuresThis is a classic JavaScript interview question:Const GREETERS = [] for (var i = 0; i ) { Greeters.push (functionreturn console.log (i)})}greeters[// /// // TenAlthoug

Front-end engineers sometimes encounter a class of interviewers during an interview, and the questions they ask are very seriously to the language itself, often not a practical question that the candidate might expect (some candidates stress the ability to work, as well as knowing that the reason is irrelevant). This kind of topic, although not logical, but to some extent, did examine the candidate's

This is my final set of front-end interview questions, used to assess the overall ability of the interviewer's JavaScript, it is a pity that nearly two years so far, almost no one has been able to correct correctly, not too difficult just because most of the interviewer too despise him. The topics are as follows: function Foo () { getName = function ()

Closure related interview questions:1.var a=0,b=0; function A (a) {a=function(b) {Console.log (a+b++);}; Console.log (a);} A (1); A (12);A (1) normal execution, Console.log (a);//1 when a function is called, a global a function is created, overwriting the original a function, but a is protected as a protected variable to form a closureWhen function a changes toA:function (b) {(a=1)Console.log (a+b++);// };(

N, that is, the first call of the n=0, that is, m=1,n=0, and in the internal call the first layer fun function fun (1,0), so O is 0;The third call. Fun (2) when M is 2, at this time the fun closure is the second call of the N=1, that is, m=2,n=1, and in the internal call the first layer fun function fun (2,1); so o is 1;The fourth time. Fun (3) is the same, but still the second return value of the call, and finally call the first layer fun function fun (3,1), so O is also 1That's the final answ

* * Is there any overload in JS? (Interview topics)(1) There is no overload in JS.(2) However, it is possible to simulate the overloaded effect in other ways (via the aruguments array)1 functionadd1 () {2 if(arguments.length==2) {3 returnArguments[0]+arguments[1];4}Else if(arguments.length==3) {5 returnArguments[0]+arguments[1]+arguments[2];6}Else if(arguments.length==4) {7