JavaScript syntax error with numeric separator

[michaelts1]

What happened?

I ran Add-ons Linter from the command line, and got a validation error:

There is a JavaScript syntax error in your code; validation cannot continue on this file.

Which points to this line of code, at column 14:
let tmp = 10_000.
It seems that the error is caused by the numeric separator.

What did you expect to happen?

I expect that Add-ons Linter will not throw any errors, since the use of numeric separators is described on https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Numeric_separators, and is supported since Firefox 70, which was released more than a year ago.

[Rob--W]

Which version of addons-linter are you using?

We rely on eslint for parsing the file, and eslint already supports it since v7.8.0 (https://github.com/eslint/eslint/releases/tag/v7.8.0).

We are currently using eslint 7.17.0 -

addons-linter/package.json

Line 54 in a8ec9db

"eslint": "7.17.0",

[michaelts1]

Running addons-linter --version gives me "2.16.0".
Running eslint --version, gives me "v7.17.0".

I created a folder containing only one file that contains only the following line: 1_0;.
Running addons-linter ./ still gives me the same error:

There is a JavaScript syntax error in your code; validation cannot continue on this file.
test.js 1 3

[Rob--W]

I see the reason... We're specifying ecmaVersion: 2020 but numeric literals require 2021 per eslint/js#448

To fix this, we need to change 2020 to 2021 at

addons-linter/src/scanners/javascript.js

Line 13 in be94690

const ECMA_VERSION = 2020;

and add a unit test (to verify that we support numeric separators) in https://github.com/mozilla/addons-linter/blob/be94690d29118a0f3c642b2803148a2699b69d67/tests/unit/scanners/test.javascript.js

Are you interested in contributing a patch?

[michaelts1]

I created a pull request to fix this issue.

[willdurand]

thanks @michaelts1!