You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
337 lines
12 KiB
337 lines
12 KiB
/**
|
|
* @fileoverview Rule to flag on declaring variables already declared in the outer scope
|
|
* @author Ilya Volodin
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Requirements
|
|
//------------------------------------------------------------------------------
|
|
|
|
const astUtils = require("./utils/ast-utils");
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Helpers
|
|
//------------------------------------------------------------------------------
|
|
|
|
const FUNC_EXPR_NODE_TYPES = new Set(["ArrowFunctionExpression", "FunctionExpression"]);
|
|
const CALL_EXPR_NODE_TYPE = new Set(["CallExpression"]);
|
|
const FOR_IN_OF_TYPE = /^For(?:In|Of)Statement$/u;
|
|
const SENTINEL_TYPE = /^(?:(?:Function|Class)(?:Declaration|Expression)|ArrowFunctionExpression|CatchClause|ImportDeclaration|ExportNamedDeclaration)$/u;
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
/** @type {import('../shared/types').Rule} */
|
|
module.exports = {
|
|
meta: {
|
|
type: "suggestion",
|
|
|
|
docs: {
|
|
description: "Disallow variable declarations from shadowing variables declared in the outer scope",
|
|
recommended: false,
|
|
url: "https://eslint.org/docs/latest/rules/no-shadow"
|
|
},
|
|
|
|
schema: [
|
|
{
|
|
type: "object",
|
|
properties: {
|
|
builtinGlobals: { type: "boolean", default: false },
|
|
hoist: { enum: ["all", "functions", "never"], default: "functions" },
|
|
allow: {
|
|
type: "array",
|
|
items: {
|
|
type: "string"
|
|
}
|
|
},
|
|
ignoreOnInitialization: { type: "boolean", default: false }
|
|
},
|
|
additionalProperties: false
|
|
}
|
|
],
|
|
|
|
messages: {
|
|
noShadow: "'{{name}}' is already declared in the upper scope on line {{shadowedLine}} column {{shadowedColumn}}.",
|
|
noShadowGlobal: "'{{name}}' is already a global variable."
|
|
}
|
|
},
|
|
|
|
create(context) {
|
|
|
|
const options = {
|
|
builtinGlobals: context.options[0] && context.options[0].builtinGlobals,
|
|
hoist: (context.options[0] && context.options[0].hoist) || "functions",
|
|
allow: (context.options[0] && context.options[0].allow) || [],
|
|
ignoreOnInitialization: context.options[0] && context.options[0].ignoreOnInitialization
|
|
};
|
|
const sourceCode = context.sourceCode;
|
|
|
|
/**
|
|
* Checks whether or not a given location is inside of the range of a given node.
|
|
* @param {ASTNode} node An node to check.
|
|
* @param {number} location A location to check.
|
|
* @returns {boolean} `true` if the location is inside of the range of the node.
|
|
*/
|
|
function isInRange(node, location) {
|
|
return node && node.range[0] <= location && location <= node.range[1];
|
|
}
|
|
|
|
/**
|
|
* Searches from the current node through its ancestry to find a matching node.
|
|
* @param {ASTNode} node a node to get.
|
|
* @param {(node: ASTNode) => boolean} match a callback that checks whether or not the node verifies its condition or not.
|
|
* @returns {ASTNode|null} the matching node.
|
|
*/
|
|
function findSelfOrAncestor(node, match) {
|
|
let currentNode = node;
|
|
|
|
while (currentNode && !match(currentNode)) {
|
|
currentNode = currentNode.parent;
|
|
}
|
|
return currentNode;
|
|
}
|
|
|
|
/**
|
|
* Finds function's outer scope.
|
|
* @param {Scope} scope Function's own scope.
|
|
* @returns {Scope} Function's outer scope.
|
|
*/
|
|
function getOuterScope(scope) {
|
|
const upper = scope.upper;
|
|
|
|
if (upper.type === "function-expression-name") {
|
|
return upper.upper;
|
|
}
|
|
return upper;
|
|
}
|
|
|
|
/**
|
|
* Checks if a variable and a shadowedVariable have the same init pattern ancestor.
|
|
* @param {Object} variable a variable to check.
|
|
* @param {Object} shadowedVariable a shadowedVariable to check.
|
|
* @returns {boolean} Whether or not the variable and the shadowedVariable have the same init pattern ancestor.
|
|
*/
|
|
function isInitPatternNode(variable, shadowedVariable) {
|
|
const outerDef = shadowedVariable.defs[0];
|
|
|
|
if (!outerDef) {
|
|
return false;
|
|
}
|
|
|
|
const { variableScope } = variable.scope;
|
|
|
|
|
|
if (!(FUNC_EXPR_NODE_TYPES.has(variableScope.block.type) && getOuterScope(variableScope) === shadowedVariable.scope)) {
|
|
return false;
|
|
}
|
|
|
|
const fun = variableScope.block;
|
|
const { parent } = fun;
|
|
|
|
const callExpression = findSelfOrAncestor(
|
|
parent,
|
|
node => CALL_EXPR_NODE_TYPE.has(node.type)
|
|
);
|
|
|
|
if (!callExpression) {
|
|
return false;
|
|
}
|
|
|
|
let node = outerDef.name;
|
|
const location = callExpression.range[1];
|
|
|
|
while (node) {
|
|
if (node.type === "VariableDeclarator") {
|
|
if (isInRange(node.init, location)) {
|
|
return true;
|
|
}
|
|
if (FOR_IN_OF_TYPE.test(node.parent.parent.type) &&
|
|
isInRange(node.parent.parent.right, location)
|
|
) {
|
|
return true;
|
|
}
|
|
break;
|
|
} else if (node.type === "AssignmentPattern") {
|
|
if (isInRange(node.right, location)) {
|
|
return true;
|
|
}
|
|
} else if (SENTINEL_TYPE.test(node.type)) {
|
|
break;
|
|
}
|
|
|
|
node = node.parent;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Check if variable name is allowed.
|
|
* @param {ASTNode} variable The variable to check.
|
|
* @returns {boolean} Whether or not the variable name is allowed.
|
|
*/
|
|
function isAllowed(variable) {
|
|
return options.allow.includes(variable.name);
|
|
}
|
|
|
|
/**
|
|
* Checks if a variable of the class name in the class scope of ClassDeclaration.
|
|
*
|
|
* ClassDeclaration creates two variables of its name into its outer scope and its class scope.
|
|
* So we should ignore the variable in the class scope.
|
|
* @param {Object} variable The variable to check.
|
|
* @returns {boolean} Whether or not the variable of the class name in the class scope of ClassDeclaration.
|
|
*/
|
|
function isDuplicatedClassNameVariable(variable) {
|
|
const block = variable.scope.block;
|
|
|
|
return block.type === "ClassDeclaration" && block.id === variable.identifiers[0];
|
|
}
|
|
|
|
/**
|
|
* Checks if a variable is inside the initializer of scopeVar.
|
|
*
|
|
* To avoid reporting at declarations such as `var a = function a() {};`.
|
|
* But it should report `var a = function(a) {};` or `var a = function() { function a() {} };`.
|
|
* @param {Object} variable The variable to check.
|
|
* @param {Object} scopeVar The scope variable to look for.
|
|
* @returns {boolean} Whether or not the variable is inside initializer of scopeVar.
|
|
*/
|
|
function isOnInitializer(variable, scopeVar) {
|
|
const outerScope = scopeVar.scope;
|
|
const outerDef = scopeVar.defs[0];
|
|
const outer = outerDef && outerDef.parent && outerDef.parent.range;
|
|
const innerScope = variable.scope;
|
|
const innerDef = variable.defs[0];
|
|
const inner = innerDef && innerDef.name.range;
|
|
|
|
return (
|
|
outer &&
|
|
inner &&
|
|
outer[0] < inner[0] &&
|
|
inner[1] < outer[1] &&
|
|
((innerDef.type === "FunctionName" && innerDef.node.type === "FunctionExpression") || innerDef.node.type === "ClassExpression") &&
|
|
outerScope === innerScope.upper
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Get a range of a variable's identifier node.
|
|
* @param {Object} variable The variable to get.
|
|
* @returns {Array|undefined} The range of the variable's identifier node.
|
|
*/
|
|
function getNameRange(variable) {
|
|
const def = variable.defs[0];
|
|
|
|
return def && def.name.range;
|
|
}
|
|
|
|
/**
|
|
* Get declared line and column of a variable.
|
|
* @param {eslint-scope.Variable} variable The variable to get.
|
|
* @returns {Object} The declared line and column of the variable.
|
|
*/
|
|
function getDeclaredLocation(variable) {
|
|
const identifier = variable.identifiers[0];
|
|
let obj;
|
|
|
|
if (identifier) {
|
|
obj = {
|
|
global: false,
|
|
line: identifier.loc.start.line,
|
|
column: identifier.loc.start.column + 1
|
|
};
|
|
} else {
|
|
obj = {
|
|
global: true
|
|
};
|
|
}
|
|
return obj;
|
|
}
|
|
|
|
/**
|
|
* Checks if a variable is in TDZ of scopeVar.
|
|
* @param {Object} variable The variable to check.
|
|
* @param {Object} scopeVar The variable of TDZ.
|
|
* @returns {boolean} Whether or not the variable is in TDZ of scopeVar.
|
|
*/
|
|
function isInTdz(variable, scopeVar) {
|
|
const outerDef = scopeVar.defs[0];
|
|
const inner = getNameRange(variable);
|
|
const outer = getNameRange(scopeVar);
|
|
|
|
return (
|
|
inner &&
|
|
outer &&
|
|
inner[1] < outer[0] &&
|
|
|
|
// Excepts FunctionDeclaration if is {"hoist":"function"}.
|
|
(options.hoist !== "functions" || !outerDef || outerDef.node.type !== "FunctionDeclaration")
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Checks the current context for shadowed variables.
|
|
* @param {Scope} scope Fixme
|
|
* @returns {void}
|
|
*/
|
|
function checkForShadows(scope) {
|
|
const variables = scope.variables;
|
|
|
|
for (let i = 0; i < variables.length; ++i) {
|
|
const variable = variables[i];
|
|
|
|
// Skips "arguments" or variables of a class name in the class scope of ClassDeclaration.
|
|
if (variable.identifiers.length === 0 ||
|
|
isDuplicatedClassNameVariable(variable) ||
|
|
isAllowed(variable)
|
|
) {
|
|
continue;
|
|
}
|
|
|
|
// Gets shadowed variable.
|
|
const shadowed = astUtils.getVariableByName(scope.upper, variable.name);
|
|
|
|
if (shadowed &&
|
|
(shadowed.identifiers.length > 0 || (options.builtinGlobals && "writeable" in shadowed)) &&
|
|
!isOnInitializer(variable, shadowed) &&
|
|
!(options.ignoreOnInitialization && isInitPatternNode(variable, shadowed)) &&
|
|
!(options.hoist !== "all" && isInTdz(variable, shadowed))
|
|
) {
|
|
const location = getDeclaredLocation(shadowed);
|
|
const messageId = location.global ? "noShadowGlobal" : "noShadow";
|
|
const data = { name: variable.name };
|
|
|
|
if (!location.global) {
|
|
data.shadowedLine = location.line;
|
|
data.shadowedColumn = location.column;
|
|
}
|
|
context.report({
|
|
node: variable.identifiers[0],
|
|
messageId,
|
|
data
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
return {
|
|
"Program:exit"(node) {
|
|
const globalScope = sourceCode.getScope(node);
|
|
const stack = globalScope.childScopes.slice();
|
|
|
|
while (stack.length) {
|
|
const scope = stack.pop();
|
|
|
|
stack.push(...scope.childScopes);
|
|
checkForShadows(scope);
|
|
}
|
|
}
|
|
};
|
|
|
|
}
|
|
};
|