Xiaomi JavaScript interview questions_javascript skills

Interview questions

1.

Copy code The code is as follows:

Please define such a function
function repeat (func, times, wait) {
}
This function can return a new function, for example, use
like this var repeatedFun = repeat(alert, 10, 5000)
Call this repeatedFun ("hellworld")
Will alert helloworld ten times, with an interval of 5 seconds each time

2.

Copy code The code is as follows:

Write a function stringconcat, which requires
var result1 = stringconcat("a", "b") result1 = "a b"
var stringconcatWithPrefix = stringconcat.prefix("hellworld");
var result2 = stringconcatWithPrefix("a", "b") result2 = "hellworld a b"

Snack solution

These two questions are all about closures. Without further ado, let’s go straight to the code.

Copy code The code is as follows:

/**
*The first question
* @param func
* @param times
* @param wait
* @returns {repeatImpl}
​*/
function repeat (func, times, wait) {
//Anonymous functions are not used to facilitate debugging
Function repeatImpl(){
      var handle,
​​​​​​ _arguments = arguments,
             i = 0;
         handle = setInterval(function(){
             i = i 1;
//Cancel the timer when the specified number of times is reached
                if(i === times){
Clearinterval (handle);
                  return;
            }
                func.apply(null, _arguments);
},wait);
}
Return repeatImpl;
}
//Test case
var repeatFun = repeat(alert, 4, 3000);
repeatFun("hellworld");
/**
*The second question
* @returns {string}
​*/
function stringconcat(){
var result = [];
Stringconcat.merge.call(null, result, arguments);
Return result.join(" ");
}
stringconcat.prefix = function(){
var _arguments = [],
​​​​ _this = this;
_this.merge.call(null, _arguments, arguments);
Return function(){
        var _args = _arguments.slice(0);
​​​​ _this.merge.call(null, _args, arguments);
          return _this.apply(null, _args);
};
};
stringconcat.merge = function(array, arrayLike){
var i = 0;
for(i = 0; i < arrayLike.length; i ){
         array.push(arrayLike[i]);
}
}
//Test case
var result1 = stringconcat("a", "b"); //result1 = "a b"
var result3 = stringconcat("c", "d"); //result1 = "a b"
var stringconcatWithPrefix = stringconcat.prefix("hellworld");
var stringconcatWithPrefix1 = stringconcat.prefix("hellworld1");
var result2 = stringconcatWithPrefix("a", "b"); //result2 = "hellworld a b"
var result4 = stringconcatWithPrefix1("c", "d"); //result2 = "hellworld a b"
alert(result1);
alert(result2);
alert(result3);
alert(result4);