[no-unnecessary-condition] False positive - Value is always falsy

[FlorinAsavoaie]

Repro

module.exports = {
  parser: "@typescript-eslint/parser",
  parserOptions: {
    ecmaVersion: 10,
    sourceType: "module",
    project: [
      "tsconfig.json"
    ],
  },
  extends: [
    "eslint:recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended",
    "plugin:@typescript-eslint/recommended-requiring-type-checking"
  ],
  rules: {
    indent: ["error", 2],
    "@typescript-eslint/indent": ["error", 2],
    "@typescript-eslint/unified-signatures": "warn",
    "@typescript-eslint/quotes": "error",
    "@typescript-eslint/promise-function-async": "error",
    "@typescript-eslint/prefer-readonly": "error",
    "@typescript-eslint/prefer-for-of": "error",
    "@typescript-eslint/no-unnecessary-condition": "error",
    "@typescript-eslint/no-magic-numbers": "error",
    "@typescript-eslint/member-ordering": "error",
    "@typescript-eslint/member-naming": "error",
    "@typescript-eslint/brace-style": "error",
    "@typescript-eslint/array-type": "error"
  },
};

/* eslint-disable @typescript-eslint/no-unused-vars */
const myFunction = (someBool?: boolean): void => {
  const test = someBool || false;
};

Expected Result
No issue with code.

Actual Result
3:28 error Unnecessary conditional, value is always falsy @typescript-eslint/no-unnecessary-condition

Versions

package	version
@typescript-eslint/eslint-plugin	2.6.1
@typescript-eslint/parser	2.6.1
TypeScript	3.6.4
ESLint	6.6.0
node	10.16.3
npm	6.12.0

[Retsam]

It's reporting an error because the ignoreRhs option isn't set, so it's treating the right hand side of the || operator as a conditional.

Unfortunately, the current version of the rule requires you to choose between false-positives with ignoreRhs off, and some false-negatives with ignoreRhs on. See #1017 . Should be fixed by #1163 , but it's a breaking change that will need to wait for the next major version bump.

[bradzacher]

As this is working as expected - I'm going to close this.