no-polymorphic-call.js

'use strict';

module.exports = {
  meta: {
    docs: {
      description: "disallow polymorphic function calls e.g.: 'array.slice()'",
      category: 'Possible Security Errors',
      recommended: true,
      url: 'https://github.com/endojs/endo/blob/master/packages/eslint-plugin/lib/rules/no-polymorphic-call.js',
    },
    type: 'problem',
    fixable: null,
    schema: [],
    supported: true,
  },
  create(context) {
    return {
      CallExpression(node) {
        if (node.callee.type !== 'MemberExpression') {
          return;
        }
        const reportHint = prepareMemberExpressionHint(node.callee);
        context.report(
          node,
          `Polymorphic call: "${reportHint}". May be vulnerable to corruption or trap`,
        );
      },
    };
  },
};

function prepareMemberExpressionHint(node) {
  const { object, property, computed } = node;
  let objectHint;
  let propertyHint;
  if (object.type === 'Identifier') {
    objectHint = object.name;
  } else if (object.type === 'MemberExpression') {
    objectHint = prepareMemberExpressionHint(object);
  } else {
    objectHint = `[[${object.type}]]`;
  }
  if (property.type === 'Identifier') {
    if (computed) {
      propertyHint = `[${property.name}]`;
    } else {
      propertyHint = property.name;
    }
  } else {
    propertyHint = `[[${property.type}]]`;
  }
  return `${objectHint}.${propertyHint}`;
}