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node_modules/eslint/lib/rules/no-alert.js 3.92 KB
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  /**
   * @fileoverview Rule to flag use of alert, confirm, prompt
   * @author Nicholas C. Zakas
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  const getPropertyName = require("../ast-utils").getStaticPropertyName;
  
  //------------------------------------------------------------------------------
  // Helpers
  //------------------------------------------------------------------------------
  
  /**
   * Checks if the given name is a prohibited identifier.
   * @param {string} name The name to check
   * @returns {boolean} Whether or not the name is prohibited.
   */
  function isProhibitedIdentifier(name) {
      return /^(alert|confirm|prompt)$/.test(name);
  }
  
  /**
   * Finds the eslint-scope reference in the given scope.
   * @param {Object} scope The scope to search.
   * @param {ASTNode} node The identifier node.
   * @returns {Reference|null} Returns the found reference or null if none were found.
   */
  function findReference(scope, node) {
      const references = scope.references.filter(reference => reference.identifier.range[0] === node.range[0] &&
              reference.identifier.range[1] === node.range[1]);
  
      if (references.length === 1) {
          return references[0];
      }
      return null;
  }
  
  /**
   * Checks if the given identifier node is shadowed in the given scope.
   * @param {Object} scope The current scope.
   * @param {string} node The identifier node to check
   * @returns {boolean} Whether or not the name is shadowed.
   */
  function isShadowed(scope, node) {
      const reference = findReference(scope, node);
  
      return reference && reference.resolved && reference.resolved.defs.length > 0;
  }
  
  /**
   * Checks if the given identifier node is a ThisExpression in the global scope or the global window property.
   * @param {Object} scope The current scope.
   * @param {string} node The identifier node to check
   * @returns {boolean} Whether or not the node is a reference to the global object.
   */
  function isGlobalThisReferenceOrGlobalWindow(scope, node) {
      if (scope.type === "global" && node.type === "ThisExpression") {
          return true;
      }
      if (node.name === "window") {
          return !isShadowed(scope, node);
      }
  
      return false;
  }
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "disallow the use of `alert`, `confirm`, and `prompt`",
              category: "Best Practices",
              recommended: false,
              url: "https://eslint.org/docs/rules/no-alert"
          },
  
          schema: [],
  
          messages: {
              unexpected: "Unexpected {{name}}."
          }
      },
  
      create(context) {
          return {
              CallExpression(node) {
                  const callee = node.callee,
                      currentScope = context.getScope();
  
                  // without window.
                  if (callee.type === "Identifier") {
                      const name = callee.name;
  
                      if (!isShadowed(currentScope, callee) && isProhibitedIdentifier(callee.name)) {
                          context.report({
                              node,
                              messageId: "unexpected",
                              data: { name }
                          });
                      }
  
                  } else if (callee.type === "MemberExpression" && isGlobalThisReferenceOrGlobalWindow(currentScope, callee.object)) {
                      const name = getPropertyName(callee);
  
                      if (isProhibitedIdentifier(name)) {
                          context.report({
                              node,
                              messageId: "unexpected",
                              data: { name }
                          });
                      }
                  }
  
              }
          };
  
      }
  };