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Replace variable names

Remove all line breaks

The next most important (and simple) thing you can do to decrease the size of the script file is to remove

all line breaks. As long as you program appropriately by including a semicolon at the end of each line,

the line breaks are of no consequence.

Many schools of thought exist about line breaks in JavaScript, but the bottom line is that line breaks

increase the readability of your code to prying eyes. Removing them is a fast, easy way to make it more

difficult for anyone to reverse engineer your code.

Replace variable names

This is the toughest optimization method to implement. Replacing variable names usually can’t be done

by hand because the process is not a standard find-and-replace text operation.

The basic idea is that any variable name (or private property of an object) should be replaced with a non-

sense variable name that has no intuitive meaning when read in the code. After all, the name of the vari-

able doesn’t matter to the interpreter, only to the developer who wants his or her code to make sense.

When it comes time to deploy the script, however, eliminate those descriptive variable names with sim-

pler, shorter ones:

function doSomething(sName,sAge,sCity){alert(sName+sAge+sCity);}

function doSomething(a1,a2,a3){alert(a1+a2+a3);}

The first line of code above is the original; the second line has the argument names replaced. By doing

this, the byte count was reduced by 16. Just imagine the savings if all the variable names in your entire

script are replaced with two-character names.

The ECMAScript cruncher

Following the four steps listed previously can be difficult. To help with the process, you can use an

external program.

Use extreme caution when trying to rename variables on your own. Using a standard

Find and Replace method in a text editor is not recommended, as the editor can’t tell

the difference between a variable name and any other text that matches the given

pattern. For example, you may have a variable named

(perhaps a Boolean indicat-

ing if a value is valid or not). If you try to replace

with another value, you also

replace the

at the end of

function

, thus rendering your entire script useless.

If for some reason removing line breaks is not an option, then — at the very least —

make sure that they are Unix format instead of Windows format. Windows uses two

characters on a line break (carriage return and line feed, ASCII codes 13 and 10

respectively); Unix uses only one. So, translating the line breaks into Unix format

from Windows still yields some byte savings.

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Deployment Issues

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