122 lines
3.6 KiB
JavaScript
122 lines
3.6 KiB
JavaScript
/**
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* @fileoverview Rule to check for "block scoped" variables by binding context
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* @author Matt DuVall <http://www.mattduvall.com>
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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module.exports = {
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meta: {
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type: "suggestion",
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docs: {
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description: "enforce the use of variables within the scope they are defined",
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category: "Best Practices",
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recommended: false,
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url: "https://eslint.org/docs/rules/block-scoped-var"
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},
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schema: [],
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messages: {
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outOfScope: "'{{name}}' used outside of binding context."
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}
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},
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create(context) {
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let stack = [];
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/**
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* Makes a block scope.
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* @param {ASTNode} node A node of a scope.
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* @returns {void}
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*/
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function enterScope(node) {
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stack.push(node.range);
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}
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/**
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* Pops the last block scope.
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* @returns {void}
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*/
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function exitScope() {
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stack.pop();
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}
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/**
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* Reports a given reference.
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* @param {eslint-scope.Reference} reference A reference to report.
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* @returns {void}
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*/
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function report(reference) {
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const identifier = reference.identifier;
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context.report({ node: identifier, messageId: "outOfScope", data: { name: identifier.name } });
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}
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/**
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* Finds and reports references which are outside of valid scopes.
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* @param {ASTNode} node A node to get variables.
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* @returns {void}
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*/
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function checkForVariables(node) {
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if (node.kind !== "var") {
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return;
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}
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// Defines a predicate to check whether or not a given reference is outside of valid scope.
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const scopeRange = stack[stack.length - 1];
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/**
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* Check if a reference is out of scope
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* @param {ASTNode} reference node to examine
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* @returns {boolean} True is its outside the scope
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* @private
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*/
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function isOutsideOfScope(reference) {
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const idRange = reference.identifier.range;
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return idRange[0] < scopeRange[0] || idRange[1] > scopeRange[1];
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}
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// Gets declared variables, and checks its references.
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const variables = context.getDeclaredVariables(node);
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for (let i = 0; i < variables.length; ++i) {
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// Reports.
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variables[i]
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.references
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.filter(isOutsideOfScope)
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.forEach(report);
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}
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}
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return {
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Program(node) {
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stack = [node.range];
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},
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// Manages scopes.
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BlockStatement: enterScope,
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"BlockStatement:exit": exitScope,
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ForStatement: enterScope,
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"ForStatement:exit": exitScope,
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ForInStatement: enterScope,
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"ForInStatement:exit": exitScope,
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ForOfStatement: enterScope,
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"ForOfStatement:exit": exitScope,
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SwitchStatement: enterScope,
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"SwitchStatement:exit": exitScope,
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CatchClause: enterScope,
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"CatchClause:exit": exitScope,
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// Finds and reports references which are outside of valid scope.
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VariableDeclaration: checkForVariables
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};
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}
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};
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