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/**
* @fileoverview Rule to flag references to undeclared variables.
* @author Mark Macdonald
* @copyright 2015 Nicholas C. Zakas. All rights reserved.
* @copyright 2013 Mark Macdonald. All rights reserved.
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
// none!
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
function isImplicitGlobal(variable) {
return variable.defs.every(function(def) {
return def.type === "ImplicitGlobalVariable";
});
}
/**
* Gets the declared variable, defined in `scope`, that `ref` refers to.
* @param {Scope} scope The scope in which to search.
* @param {Reference} ref The reference to find in the scope.
* @returns {Variable} The variable, or null if ref refers to an undeclared variable.
*/
function getDeclaredGlobalVariable(scope, ref) {
var declaredGlobal = null;
scope.variables.some(function(variable) {
if (variable.name === ref.identifier.name) {
// If it's an implicit global, it must have a `writeable` field (indicating it was declared)
if (!isImplicitGlobal(variable) || {}.hasOwnProperty.call(variable, "writeable")) {
declaredGlobal = variable;
return true;
}
}
return false;
});
return declaredGlobal;
}
/**
* Checks if the given node is the argument of a typeof operator.
* @param {ASTNode} node The AST node being checked.
* @returns {boolean} Whether or not the node is the argument of a typeof operator.
*/
function hasTypeOfOperator(node) {
var parent = node.parent;
return parent.type === "UnaryExpression" && parent.operator === "typeof";
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(context) {
var NOT_DEFINED_MESSAGE = "\"{{name}}\" is not defined.",
READ_ONLY_MESSAGE = "\"{{name}}\" is read only.";
return {
"Program:exit": function(/*node*/) {
var globalScope = context.getScope();
globalScope.through.forEach(function(ref) {
var variable = getDeclaredGlobalVariable(globalScope, ref),
name = ref.identifier.name;
if (hasTypeOfOperator(ref.identifier)) {
return;
}
if (!variable) {
context.report(ref.identifier, NOT_DEFINED_MESSAGE, { name: name });
} else if (ref.isWrite() && variable.writeable === false) {
context.report(ref.identifier, READ_ONLY_MESSAGE, { name: name });
}
});
}
};
};