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#Whta is another word for variable. code#

const – is like let, but the value of the variable can’t be changed.

Normally we don’t use it at all, but we’ll cover subtle differences from let in the chapter The old "var", just in case you need them.

var – is an old-school variable declaration.

let – is a modern variable declaration.

We can declare variables to store data by using the var, let, or const keywords. Using different variables for different values can even help the engine optimize your code.

#Whta is another word for variable. code#

Modern JavaScript minifiers and browsers optimize code well enough, so it won’t create performance issues. Such programmers save a little bit on variable declaration but lose ten times more on debugging. What’s inside the box now? Who knows? We need to come closer and check. There are some lazy programmers who, instead of declaring new variables, tend to reuse existing ones.Īs a result, their variables are like boxes into which people throw different things without changing their stickers. Sounds simple? Indeed it is, but creating descriptive and concise variable names in practice is not. If a site visitor is called a “user” then we should name related variables currentUser or newUser instead of currentVisitor or newManInTown. Agree on terms within your team and in your own mind.It’s only okay to use them if the context of the code makes it exceptionally obvious which data or value the variable is referencing. Examples of bad names are data and value. Make names maximally descriptive and concise.Stay away from abbreviations or short names like a, b, c, unless you really know what you’re doing.Use human-readable names like userName or shoppingCart.Please spend time thinking about the right name for a variable before declaring it. Or, in other words, when the variables have good names. When we return to some code after doing something else for a while, it’s much easier to find information that is well-labeled. In a real project, most of the time is spent modifying and extending an existing code base rather than writing something completely separate from scratch. A quick glance at variable names can reveal which code was written by a beginner versus an experienced developer. Variable naming is one of the most important and complex skills in programming. Talking about variables, there’s one more extremely important thing.Ī variable name should have a clean, obvious meaning, describing the data that it stores. In other words, capital-named constants are only used as aliases for “hard-coded” values. But it’s still a constant because it doesn’t change after assignment. The value of pageLoadTime is not known prior to the page load, so it’s named normally.

Const pageLoadTime = /* time taken by a webpage to load */