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Node.js for PHP Developers by Daniel Howard

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Chapter 7. Variables

Now that PHP syntax has been converted to Node.js in the previous chapter, we can turn our attention to variables, which are a little more interesting and complicated to convert.

In PHP, a variable name always starts with a dollar sign ($). For example, $a and $colors are PHP variable names, but a and colors are not. In Node.js, a variable name may start with a dollar sign ($), but does not have to. So, in Node.js, $a, $colors, a, and colors are all valid Node.js variable names.

However, in Node.js, even though it is perfectly legal, it is a widely accepted common practice to avoid variable names that begin with a dollar sign ($). It is so widely accepted that Node.js code that uses variable names that start with a dollar sign ($) looks very, very strange to Node.js developers. To accommodate this practice, it is recommended that PHP variable names be converted to Node.js variable names by removing the dollar sign ($). For example, the PHP variables $a and $colors should be converted to the Node.js variables, a and colors.

The allowed characters in a PHP variable name is a subset of the allowed characters in a Node.js variable name. It is recommended that variable names, excluding the initial dollar sign ($) for PHP variables, begin with an alphabetic character of either case, that is, a to z or A to Z, and have the remaining characters be zero or more characters that are alphabetic characters of any case (a to z or A to Z), underscores ( _ ), or digits (0 to 9). ...

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