Spaces in equal signs

Question

I'm just wondering is there a difference in performance using removing spaces before and after equal signs. Like this two code snippets.

first

int i = 0;

second

int i=0;

I'm using the first one, but my friend who is learning html/javascript told me that my coding is inefficient. Is it true in html/javascript? And is it a huge bump in the performance? Will it also be same in c++/c# and other programming languages? And about the indent, he said 3 spaces is better that tab. But I already used to code like this. So I just want to know if he is correct.

Answer 1

Your friend is a bit misguided.

The extra spaces in the code will make a small difference in the size of the JS file which could make a small difference in the download speed, though I'd be surprised if it was noticeable or meaningful.

The extra spaces are unlikely to make a meaningful difference in the time to parse the file.

Once the file is parsed, the extra spaces will not make any difference in execution speed since they are not part of the parsed code.

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If you really want to optimize download or parse speed, the way to do that is to write your code in the most readable fashion possible for best maintainability and then use a minimizer for the deployed code and this is a standard practice by many web sites. This will give you the best of both worlds - maintainable, readable code and minimum deployed size.

A minimizer will remove all unnecessary spacing, shorten the names of variables, remove comments, collapse lines, etc... all designed to make the deployed code as small as possible without changing the run-time meaning of the code at all.

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C++ is a compiled language. As such, only the compiler that the developer uses sees any extra spaces (same with comments). Those spaces are gone once the code has been compiled into native code which is what the end-user gets and runs. So, issues about spaces between elements in a line are simply not applicable at all for C++.

Javascript is an interpreted language. That means the source code is downloaded to the browser and the browser then parses the code at runtime into some opcode form that the interpreter can run. The spaces in Javascript will be part of the downloaded code (if you don't use a minimizer to remove them), but once the code is parsed, those extra spaces are not part of the run-time performance of the code. Thus, the spaces could have a small influence on the download time and perhaps an even smaller influence on the parse time (though I'm guessing unlikely to be measurable or meaningful). As I said above, the way to optimize this for Javascript is to use spaces to enhance readability in the source code and then run a minimizer over the code to generate a deployed version of the code to minimize the deployed size of the file. This preserves maximum readability and minimizes download size.

Answer 2

There is little (javascript) to no (c#, c++, Java) difference in performance. In the compiled languages in particular, the source code compiles to the exact same machine code.

Using spaces instead of tabs can be a good idea, but not because of performance. Rather, if you aren't careful, use of tabs can result in "tab rot", where there are tabs in some places and spaces in others, and the indentation of the source code depends on your tab settings, making it hard to read.