Much like peanut butter and jelly, or Celebrities and The Paparazzi, operators and expressions go together.
So let’s go ahead and jump right into Java Script Operators and Expressions.
I have been seeing && overused here at work for assignment statements.
The concern is twofold: 1) The 'indicator' check is sometimes a function with overhead that developers don't account for.
Here are some examples you may find odd but keep reading as it is explained later.
var user = undefined; var username = user && user.username; // no error, "username" assigned value of "user" which is undefined user = ; username = user && user.username; // no error, "username" assigned 'Johnny' user = ; username = user && user.username; // no error, "username" assigned value of "username" which is undefined Explanation: In the guard operation, each term is evaluated left-to-right one at a time.If a value evaluated is falsy, evaluation stops and that value is then assigned.If the last item is reached, it is then assigned whether or not it is falsy.In the following table, the operators at the top have the highest precedence, and the lowest of course have the lowest precedence.With Java Script being a client side language, we have the added benefit of being able to test small snippets of code very easily from the console of our web browser.Even the simplest lines of code can be an expression.Extremely simple expressions are called primary expressions yet the more complex expressions are what we are more interested in.If there was a need to change the operator precedence we could rewrite the expression like so to alter the result to 100.The main idea is to remember that by using parentheses, you can set the precedence in your Java Script as needed.By commenting, you are accepting the DISQUS terms of service.Operators are the symbols between values that allow different operations like addition, subtraction, multiplication, and more. Code located between parentheses evaluates first as Java Script solves each operation moving from left to right.