[JS Operation Performance Series] Methods of splicing strings and performance comparison

To splice multiple strings together, there are usually three methods, which are often used in practice.

Use the string concatenation operator '+', 'string1' + 'string2' + ...

Use the join function of the array. First write the string into a temporary array, and then call the join method of the array to connect the string elements.

Use the concat function of string.

Method one: Use the string concatenation character '+'

var concat1 = function(str1, str2){
    return str1 + str2;
};

Method two: Use the join function of the array

var concat2 = function(str1, str2){
    var arr = [];
    arr.push(str1);
    arr.push(str2);

    return arr.join();
};

Method three: Use the concat function of the string

var concat3 = function(str1, str2){
    return str1.concat(str2);
};

Performance summary

I used Benchmark locally to evaluate the above The performance of the two methods was compared. The test environment was Testing in Chrome 46.0.2490 / Mac OS Much higher.

Of course, this is only a test in the chrome 46 environment and does not represent all browser platforms.

There is also a similar performance test in jsPerf https://jsperf.com/concat-vs-...

The test results are as follows:

It will be more efficient to use join in old browsers (ie7-).

In modern browsers, try to use "+" for more efficiency.

Of course, "+" may not necessarily be faster than join in a few modern browsers (for example, Safari 5.0.5, Opera 11.10)

Itself is a string array, and direct join would be better.

Between "+" and concat, of course it is better to use "+", which is convenient, intuitive and efficient.