Current File : /var/www/html/node_modules/eslint/lib/rules/no-eval.js
/**
* @fileoverview Rule to flag use of eval() statement
* @author Nicholas C. Zakas
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
const candidatesOfGlobalObject = Object.freeze([
"global",
"window",
"globalThis"
]);
/**
* Checks a given node is a MemberExpression node which has the specified name's
* property.
* @param {ASTNode} node A node to check.
* @param {string} name A name to check.
* @returns {boolean} `true` if the node is a MemberExpression node which has
* the specified name's property
*/
function isMember(node, name) {
return astUtils.isSpecificMemberAccess(node, null, name);
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "disallow the use of `eval()`",
recommended: false,
url: "https://eslint.org/docs/rules/no-eval"
},
schema: [
{
type: "object",
properties: {
allowIndirect: { type: "boolean", default: false }
},
additionalProperties: false
}
],
messages: {
unexpected: "eval can be harmful."
}
},
create(context) {
const allowIndirect = Boolean(
context.options[0] &&
context.options[0].allowIndirect
);
const sourceCode = context.getSourceCode();
let funcInfo = null;
/**
* Pushs a variable scope (Program or Function) information to the stack.
*
* This is used in order to check whether or not `this` binding is a
* reference to the global object.
* @param {ASTNode} node A node of the scope. This is one of Program,
* FunctionDeclaration, FunctionExpression, and ArrowFunctionExpression.
* @returns {void}
*/
function enterVarScope(node) {
const strict = context.getScope().isStrict;
funcInfo = {
upper: funcInfo,
node,
strict,
defaultThis: false,
initialized: strict
};
}
/**
* Pops a variable scope from the stack.
* @returns {void}
*/
function exitVarScope() {
funcInfo = funcInfo.upper;
}
/**
* Reports a given node.
*
* `node` is `Identifier` or `MemberExpression`.
* The parent of `node` might be `CallExpression`.
*
* The location of the report is always `eval` `Identifier` (or possibly
* `Literal`). The type of the report is `CallExpression` if the parent is
* `CallExpression`. Otherwise, it's the given node type.
* @param {ASTNode} node A node to report.
* @returns {void}
*/
function report(node) {
const parent = node.parent;
const locationNode = node.type === "MemberExpression"
? node.property
: node;
const reportNode = parent.type === "CallExpression" && parent.callee === node
? parent
: node;
context.report({
node: reportNode,
loc: locationNode.loc,
messageId: "unexpected"
});
}
/**
* Reports accesses of `eval` via the global object.
* @param {eslint-scope.Scope} globalScope The global scope.
* @returns {void}
*/
function reportAccessingEvalViaGlobalObject(globalScope) {
for (let i = 0; i < candidatesOfGlobalObject.length; ++i) {
const name = candidatesOfGlobalObject[i];
const variable = astUtils.getVariableByName(globalScope, name);
if (!variable) {
continue;
}
const references = variable.references;
for (let j = 0; j < references.length; ++j) {
const identifier = references[j].identifier;
let node = identifier.parent;
// To detect code like `window.window.eval`.
while (isMember(node, name)) {
node = node.parent;
}
// Reports.
if (isMember(node, "eval")) {
report(node);
}
}
}
}
/**
* Reports all accesses of `eval` (excludes direct calls to eval).
* @param {eslint-scope.Scope} globalScope The global scope.
* @returns {void}
*/
function reportAccessingEval(globalScope) {
const variable = astUtils.getVariableByName(globalScope, "eval");
if (!variable) {
return;
}
const references = variable.references;
for (let i = 0; i < references.length; ++i) {
const reference = references[i];
const id = reference.identifier;
if (id.name === "eval" && !astUtils.isCallee(id)) {
// Is accessing to eval (excludes direct calls to eval)
report(id);
}
}
}
if (allowIndirect) {
// Checks only direct calls to eval. It's simple!
return {
"CallExpression:exit"(node) {
const callee = node.callee;
/*
* Optional call (`eval?.("code")`) is not direct eval.
* The direct eval is only step 6.a.vi of https://tc39.es/ecma262/#sec-function-calls-runtime-semantics-evaluation
* But the optional call is https://tc39.es/ecma262/#sec-optional-chaining-chain-evaluation
*/
if (!node.optional && astUtils.isSpecificId(callee, "eval")) {
report(callee);
}
}
};
}
return {
"CallExpression:exit"(node) {
const callee = node.callee;
if (astUtils.isSpecificId(callee, "eval")) {
report(callee);
}
},
Program(node) {
const scope = context.getScope(),
features = context.parserOptions.ecmaFeatures || {},
strict =
scope.isStrict ||
node.sourceType === "module" ||
(features.globalReturn && scope.childScopes[0].isStrict);
funcInfo = {
upper: null,
node,
strict,
defaultThis: true,
initialized: true
};
},
"Program:exit"() {
const globalScope = context.getScope();
exitVarScope();
reportAccessingEval(globalScope);
reportAccessingEvalViaGlobalObject(globalScope);
},
FunctionDeclaration: enterVarScope,
"FunctionDeclaration:exit": exitVarScope,
FunctionExpression: enterVarScope,
"FunctionExpression:exit": exitVarScope,
ArrowFunctionExpression: enterVarScope,
"ArrowFunctionExpression:exit": exitVarScope,
"PropertyDefinition > *.value": enterVarScope,
"PropertyDefinition > *.value:exit": exitVarScope,
StaticBlock: enterVarScope,
"StaticBlock:exit": exitVarScope,
ThisExpression(node) {
if (!isMember(node.parent, "eval")) {
return;
}
/*
* `this.eval` is found.
* Checks whether or not the value of `this` is the global object.
*/
if (!funcInfo.initialized) {
funcInfo.initialized = true;
funcInfo.defaultThis = astUtils.isDefaultThisBinding(
funcInfo.node,
sourceCode
);
}
if (!funcInfo.strict && funcInfo.defaultThis) {
// `this.eval` is possible built-in `eval`.
report(node.parent);
}
}
};
}
};
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