Array, String and .join( )

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Is JavaScript a pass-by-reference or pass-by-value language? 29 answers

Javascript by reference vs. by value [duplicate] 4 answers

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It almost works as you wrote it. If you return str from the function, you can set newstr that way.

//empty string var newStr =''; 
var myArr = ['it','was', 'the', 'best', 'of', 'times']; 
var rejoiner = function (arr) { 
    var str = arr.join(' '); //checking that the function is working 
    console.log(str); 
    return str;
};

newStr = rejoiner(myArr);

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Function parameters are copies. It's as if you'd written

var arr = myArr, str = newStr;
str = arr.join(' ');
console.log(str);

Assigning to str doesn't change newStr . In JavaScript, f(x) can't change x .

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It just worked fine for me!:

//empty string
            var newStr ='';

            var myArr = ['it','was', 'the', 'best', 'of', 'times'];

            var rejoiner = function (arr, str) {
              str = arr.join(' ');
              //checking that the function is working
              console.log(str);
            }

            rejoiner(myArr, newStr);

Check your console log!

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