static-vars.js

module.exports = function(context) {
  var variables = {};
  return {
    Identifier: function(node) {
      // Start tracking a variable; it might be used to create an identifier
      // we don't allow.
      if (node.parent.type === 'VariableDeclarator') {
        variables[node.name] = {
          ops: 0,
          reported: false,
          value: node.parent.init.value,
        };
      }

      console.log(node.name, variables[node.name], node)
      if (node.parent.type === 'AssignmentExpression') {
        if (node.parent.right && node.parent.right.type === 'Literal') {
          if (node.parent.operator === '+=') {
            variables[node.name].value += node.parent.right.value;
            variables[node.name].ops++;
          }

          if (node.parent.operator === '-=') {
            variables[node.name].value -= node.parent.right.value;
            variables[node.name].ops++;
          }
        }
      }

      if (node.parent.type === 'BinaryExpression') {
        if (node.parent.operator === '+') {
          if (node.parent.right.type === 'Literal') {
            variables[node.name].value = variables[node.name].value +
                                         node.parent.right.value;
            variables[node.name].ops++;
          }

          if (node.parent.right.type === 'Identifier') {
            variables[node.name].value = variables[node.name].value +
              variables[node.parent.right.name].value;
          }
        }
      }

      // Catches obsfucated calls to `mozIndexedDB`.
      for (var varName in variables) {
        if (variables[varName].value === 'mozIndexedDB' &&
            variables[varName].ops > 0 &&
            variables[varName].reported === false) {
          variables[varName].reported = true;
          return context.report(node, 'mozIndexedDB_possible');
        }
      }
    },
  };
};