检测到一个变量和一个 function 在 Javascript 中具有相同名称的 ESlint 规则？

Question

I happened to name a variable the same as a function in Node.js. This did not go very well, Node 10 did not like it. And since this was a hook function (not called from the UI of the app) it took some time before I discovered what went wrong.

Is there some ESLint rule that can discover these type of bugs? This is under Firebase and and ESLint is run during the deploy to production server.

The actual conflicting use of the variable name was in the same block, something like this: const a = a(x) .

Answer 1

I don't think a tool like this could exist for JavaScript, as JavaScript doesn't really disambiguate the type of object assigned to the variable.

function a() {

}

... is basically equivalent to:

var a = function () {

};

Additionally, the value of a in this example can be reassigned later.

A linter may help you, and there may be some help in some IDEs, but they won't truly know the intention of the programmer.

Answer 2

There is a no-redeclare rule you can set in ESLint , which tells you the problematic line in your code.

/*eslint no-redeclare: "error"*/

function a() {}
const a = a();

=> 4:5  error  'a' is already defined  no-redeclare

Also ESLint will raises an error with the standard configuration.

function a() {}
var a = a();

=> 4:5  error  Parsing error: Identifier 'a' has already been declared

Of course, with const , you will get a syntax error with the line as well if you try to run your script.