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node_modules/eslint/lib/rules/no-bitwise.js 3.44 KB
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  /**
   * @fileoverview Rule to flag bitwise identifiers
   * @author Nicholas C. Zakas
   */
  
  "use strict";
  
  /*
   *
   * Set of bitwise operators.
   *
   */
  const BITWISE_OPERATORS = [
      "^", "|", "&", "<<", ">>", ">>>",
      "^=", "|=", "&=", "<<=", ">>=", ">>>=",
      "~"
  ];
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "disallow bitwise operators",
              category: "Stylistic Issues",
              recommended: false,
              url: "https://eslint.org/docs/rules/no-bitwise"
          },
  
          schema: [
              {
                  type: "object",
                  properties: {
                      allow: {
                          type: "array",
                          items: {
                              enum: BITWISE_OPERATORS
                          },
                          uniqueItems: true
                      },
                      int32Hint: {
                          type: "boolean"
                      }
                  },
                  additionalProperties: false
              }
          ],
  
          messages: {
              unexpected: "Unexpected use of '{{operator}}'."
          }
      },
  
      create(context) {
          const options = context.options[0] || {};
          const allowed = options.allow || [];
          const int32Hint = options.int32Hint === true;
  
          /**
           * Reports an unexpected use of a bitwise operator.
           * @param   {ASTNode} node Node which contains the bitwise operator.
           * @returns {void}
           */
          function report(node) {
              context.report({ node, messageId: "unexpected", data: { operator: node.operator } });
          }
  
          /**
           * Checks if the given node has a bitwise operator.
           * @param   {ASTNode} node The node to check.
           * @returns {boolean} Whether or not the node has a bitwise operator.
           */
          function hasBitwiseOperator(node) {
              return BITWISE_OPERATORS.indexOf(node.operator) !== -1;
          }
  
          /**
           * Checks if exceptions were provided, e.g. `{ allow: ['~', '|'] }`.
           * @param   {ASTNode} node The node to check.
           * @returns {boolean} Whether or not the node has a bitwise operator.
           */
          function allowedOperator(node) {
              return allowed.indexOf(node.operator) !== -1;
          }
  
          /**
           * Checks if the given bitwise operator is used for integer typecasting, i.e. "|0"
           * @param   {ASTNode} node The node to check.
           * @returns {boolean} whether the node is used in integer typecasting.
           */
          function isInt32Hint(node) {
              return int32Hint && node.operator === "|" && node.right &&
                node.right.type === "Literal" && node.right.value === 0;
          }
  
          /**
           * Report if the given node contains a bitwise operator.
           * @param   {ASTNode} node The node to check.
           * @returns {void}
           */
          function checkNodeForBitwiseOperator(node) {
              if (hasBitwiseOperator(node) && !allowedOperator(node) && !isInt32Hint(node)) {
                  report(node);
              }
          }
  
          return {
              AssignmentExpression: checkNodeForBitwiseOperator,
              BinaryExpression: checkNodeForBitwiseOperator,
              UnaryExpression: checkNodeForBitwiseOperator
          };
  
      }
  };