block-scoped-var.js
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/**
* @fileoverview Rule to check for "block scoped" variables by binding context
* @author Matt DuVall <http://www.mattduvall.com>
* @copyright 2015 Toru Nagashima. All rights reserved.
* @copyright 2015 Mathieu M-Gosselin. All rights reserved.
*/
"use strict";
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Collects unresolved references from the global scope, then creates a map to references from its name.
* @param {RuleContext} context - The current context.
* @returns {object} A map object. Its key is the variable names. Its value is the references of each variable.
*/
function collectUnresolvedReferences(context) {
var unresolved = Object.create(null);
var references = context.getScope().through;
for (var i = 0; i < references.length; ++i) {
var reference = references[i];
var name = reference.identifier.name;
if (name in unresolved === false) {
unresolved[name] = [];
}
unresolved[name].push(reference);
}
return unresolved;
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(context) {
var unresolvedReferences = Object.create(null);
var stack = [];
/**
* Makes a block scope.
* @param {ASTNode} node - A node of a scope.
* @returns {void}
*/
function enterScope(node) {
stack.push(node.range);
}
/**
* Pops the last block scope.
* @returns {void}
*/
function exitScope() {
stack.pop();
}
/**
* Reports a given reference.
* @param {escope.Reference} reference - A reference to report.
* @returns {void}
*/
function report(reference) {
var identifier = reference.identifier;
context.report(
identifier,
"\"{{name}}\" used outside of binding context.",
{name: identifier.name});
}
/**
* Finds and reports references which are outside of valid scopes.
* @param {ASTNode} node - A node to get variables.
* @returns {void}
*/
function checkForVariables(node) {
if (node.kind !== "var") {
return;
}
var isGlobal = context.getScope().type === "global";
// Defines a predicate to check whether or not a given reference is outside of valid scope.
var scopeRange = stack[stack.length - 1];
/**
* Check if a reference is out of scope
* @param {ASTNode} reference node to examine
* @returns {boolean} True is its outside the scope
* @private
*/
function isOutsideOfScope(reference) {
var idRange = reference.identifier.range;
return idRange[0] < scopeRange[0] || idRange[1] > scopeRange[1];
}
// Gets declared variables, and checks its references.
var variables = context.getDeclaredVariables(node);
for (var i = 0; i < variables.length; ++i) {
var variable = variables[i];
var references = variable.references;
// Global variables are not resolved.
// In this case, use unresolved references.
if (isGlobal && variable.name in unresolvedReferences) {
references = unresolvedReferences[variable.name];
}
// Reports.
references.filter(isOutsideOfScope).forEach(report);
}
}
return {
"Program": function(node) {
unresolvedReferences = collectUnresolvedReferences(context);
stack = [node.range];
},
// Manages scopes.
"BlockStatement": enterScope,
"BlockStatement:exit": exitScope,
"ForStatement": enterScope,
"ForStatement:exit": exitScope,
"ForInStatement": enterScope,
"ForInStatement:exit": exitScope,
"ForOfStatement": enterScope,
"ForOfStatement:exit": exitScope,
"SwitchStatement": enterScope,
"SwitchStatement:exit": exitScope,
"CatchClause": enterScope,
"CatchClause:exit": exitScope,
// Finds and reports references which are outside of valid scope.
"VariableDeclaration": checkForVariables
};
};
module.exports.schema = [];