forked from eslint/eslint
/
no-inner-declarations.js
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/
no-inner-declarations.js
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/**
* @fileoverview Rule to enforce declarations in program or function body root.
* @author Brandon Mills
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
const validParent = ["Program", "ExportNamedDeclaration", "ExportDefaultDeclaration"];
const validBlockStatementParent = ["FunctionDeclaration", "FunctionExpression", "ArrowFunctionExpression"];
module.exports = {
meta: {
type: "problem",
docs: {
description: "disallow variable or `function` declarations in nested blocks",
category: "Possible Errors",
recommended: true,
url: "https://eslint.org/docs/rules/no-inner-declarations"
},
schema: [
{
enum: ["functions", "both"]
}
],
messages: {
moveDeclToRoot: "Move {{type}} declaration to {{body}} root."
}
},
create(context) {
/**
* Ensure that a given node is at a program or function body's root.
* @param {ASTNode} node Declaration node to check.
* @returns {void}
*/
function check(node) {
const ancestors = context.getAncestors();
let ancestor = ancestors.pop();
if (
ancestor.type === "BlockStatement" &&
!!~validBlockStatementParent.indexOf(ancestor.parent.type)
) {
return;
}
if ((~validParent.indexOf(ancestor.type))) {
return;
}
let parentsListToCheck = ancestor.type === "BlockStatement" ? validBlockStatementParent : validParent;
while (ancestor && !~parentsListToCheck.indexOf(ancestor.type)) {
ancestor = ancestors.pop();
if (ancestor.type === "BlockStatement") {
ancestor = ancestor.parent;
parentsListToCheck = validBlockStatementParent;
} else {
parentsListToCheck = validParent;
}
}
context.report({
node,
messageId: "moveDeclToRoot",
data: {
type: (node.type === "FunctionDeclaration" ? "function" : "variable"),
body: (ancestor.type === "Program" ? "program" : "function body")
}
});
}
return {
FunctionDeclaration: check,
VariableDeclaration(node) {
if (context.options[0] === "both" && node.kind === "var") {
check(node);
}
}
};
}
};