complete/prefer-postfix-plusplus

💼 This rule is enabled in the ✅ recommended config.

📝 Require i++ instead of ++i and i-- instead of --i.

💭 This rule requires type information.

Rule Details

Most of the time, the ++ operator is used inside of a for loop, which is pretty easy to understand. In this simple case, switching i++ to ++i does not functionally change the program in any way. However, this is not always the case. In some situations, changing ++i to i++ does result in functionally different code. In these cases, it is usually done specifically by the programmer to take take advantage of the prefix functionality.

Sometimes, using prefix ++ and -- is the most concise way to write code. But since this usage is so rare in JavaScript/TypeScript, other people reading the code can get confused. So, it can be a good idea to replace prefix operators with more standard code, which can make things a bit less arcane at the cost of a little verbosity.

Thus, this rule is meant to be used with the no-unsafe-plusplus ESLint rule, which ensures that code like in the previous example can be identified and removed. The remaining cases of ++i in your code-base can be safety converted to the more-standard i++, which will make your code more uniform.

// Bad
++foo;
--foo;

// Good
foo++;
foo--;

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Resources

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