babel/eslint/babel-eslint-plugin/rules/no-unused-expressions.js
Nicolò Ribaudo b4c42601d1
Fix linting in ESLint packages (#10712)
* Lint eslint/*

* Run "make fix-js"

* Fix remaining problems

* Remove linting from subpackages

* Remove husky

* Add back eslint dep
2019-11-14 22:05:26 +01:00

65 lines
1.7 KiB
JavaScript

"use strict";
const ruleComposer = require("eslint-rule-composer");
const eslint = require("eslint");
const rule = new eslint.Linter().getRules().get("no-unused-expressions");
/**
* @param {ASTNode} node - any node
* @returns {boolean} whether the given node is either an IfStatement or an
* ExpressionStatement and is the last node in the body of a BlockStatement
*/
function isFinalStatementInBlockStatement(node) {
const parent = node.parent;
return (
/^(?:If|Expression)Statement$/.test(node.type) &&
parent.type === "BlockStatement" &&
parent.body[parent.body.length - 1] === node
);
}
/**
* @param {ASTNode} node - any node
* @returns {boolean} whether the given node represents an unbroken chain of
* tail ExpressionStatements and IfStatements within a DoExpression
*/
function isInDoStatement(node) {
if (!node) return false;
if (node.type === "DoExpression") return true;
// this is an `else if`
if (
node.type === "IfStatement" &&
node.parent &&
node.parent.type === "IfStatement"
) {
return isInDoStatement(node.parent);
}
if (isFinalStatementInBlockStatement(node)) {
return isInDoStatement(node.parent.parent);
}
return false;
}
/**
* @param {ASTNode} node - any node
* @returns {boolean} whether the given node is an optional call expression,
* see https://github.com/tc39/proposal-optional-chaining
*/
function isOptionalCallExpression(node) {
return (
!!node &&
node.type === "ExpressionStatement" &&
node.expression.type === "OptionalCallExpression"
);
}
module.exports = ruleComposer.filterReports(
rule,
problem =>
!isInDoStatement(problem.node) && !isOptionalCallExpression(problem.node)
);