Eslint SyntaxError: Unexpected token = - npm

Question

I've encountered the following error while using eslint command in my project:
$ eslint ./src/ --max-warnings 69 --ext .js,.jsx,.ts,.tsx
Oops! Something went wrong! :(
ESLint: 7.7.0
.../node_modules/language-tags/lib/Tag.js:17
static ERR_DEPRECATED = 1;
^
SyntaxError: Unexpected token =
at new Script (vm.js:83:7)
at NativeCompileCache._moduleCompile (.../node_modules/v8-compile-cache/v8-compile-cache.js:240:18)
at Module._compile (.../node_modules/v8-compile-cache/v8-compile-cache.js:184:36)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Module.require (internal/modules/cjs/loader.js:692:17)
at require (.../node_modules/v8-compile-cache/v8-compile-cache.js:159:20)
at Object.<anonymous> (.../node_modules/language-tags/lib/index.js:11:11)
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
I am using the following plugins and configs for eslint:
{
"#typescript-eslint/eslint-plugin": "4.15.2",
"#typescript-eslint/parser": "4.15.2",
"eslint": "7.7.0",
"eslint-config-airbnb": "18.2.1",
"eslint-config-airbnb-typescript": "9.0.0",
"eslint-config-prettier": "8.3.0",
"eslint-import-resolver-typescript": "2.4.0",
"eslint-plugin-cypress": "2.12.1",
"eslint-plugin-dirnames": "1.0.3",
"eslint-plugin-import": "2.23.4",
"eslint-plugin-jsx-a11y": "6.4.1",
"eslint-plugin-prettier": "3.4.0",
"eslint-plugin-react": "7.24.0",
"eslint-plugin-react-hooks": "4.2.0",
"eslint-plugin-simple-import-sort": "5.0.3",
"eslint-plugin-unicorn": "18.0.1"
}
I've tried to reproduce the correct package configuration which worked fine before I started switching my project from npm to yarn v1 (this problem happened because of that). But current yarn.lock is about 25000 lines long and it is tough to compare it to package-lock.json.

Answer 1

I solved this problem by myself eventually and want to share the solution.
The problem lied in the eslint-plugin-jsx-a11y#6.4.1 package.
Its dependencies are listed below:
dependencies:
"#babel/runtime" "^7.11.2"
aria-query "^4.2.2"
array-includes "^3.1.1"
ast-types-flow "^0.0.7"
axe-core "^4.0.2"
axobject-query "^2.2.0"
damerau-levenshtein "^1.0.6"
emoji-regex "^9.0.0"
has "^1.0.3"
jsx-ast-utils "^3.1.0"
language-tags "^1.0.5"
As it turns out, yarn v1 resolved the dependency language-tags#^1.0.5 as language-tags#1.0.7 which caused the eslint command to stop working altogether.
language-tags#^1.0.5:
version "1.0.7"
resolved ".../npm/language-tags/-/language-tags-1.0.7.tgz#41cc248730f3f12a452c2e2efe32bc0bbce67967"
integrity ...
dependencies:
language-subtag-registry "^0.3.20"
So the solution is to either change the version of language-tags in your lock file from 1.0.7 to 1.0.5 or provide a yarn resolution where you would specify the desired package version
"resolutions": {
"language-tags": "1.0.5"
}