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105 lines
3.5 KiB
105 lines
3.5 KiB
/**
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* @fileoverview Rule to flag use of variables before they are defined
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* @author Ilya Volodin
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* @copyright 2013 Ilya Volodin. All rights reserved.
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Constants
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//------------------------------------------------------------------------------
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var NO_FUNC = "nofunc";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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module.exports = function(context) {
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/**
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* Finds variable declarations in a given scope.
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* @param {string} name The variable name to find.
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* @param {Scope} scope The scope to search in.
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* @returns {Object} The variable declaration object.
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* @private
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*/
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function findDeclaration(name, scope) {
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// try searching in the current scope first
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for (var i = 0, l = scope.variables.length; i < l; i++) {
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if (scope.variables[i].name === name) {
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return scope.variables[i];
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}
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}
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// check if there's upper scope and call recursivly till we find the variable
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if (scope.upper) {
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return findDeclaration(name, scope.upper);
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}
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}
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/**
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* Finds and validates all variables in a given scope.
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* @param {Scope} scope The scope object.
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* @returns {void}
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* @private
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*/
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function findVariablesInScope(scope) {
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var typeOption = context.options[0];
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function checkLocationAndReport(reference, declaration) {
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if (typeOption !== NO_FUNC || declaration.defs[0].type !== "FunctionName") {
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if (declaration.identifiers[0].range[1] > reference.identifier.range[1]) {
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context.report(reference.identifier, "{{a}} was used before it was defined", {a: reference.identifier.name});
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}
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}
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}
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scope.references.forEach(function(reference) {
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// if the reference is resolved check for declaration location
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// if not, it could be function invocation, try to find manually
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if (reference.resolved && reference.resolved.identifiers.length > 0) {
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checkLocationAndReport(reference, reference.resolved);
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} else {
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var declaration = findDeclaration(reference.identifier.name, scope);
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// if there're no identifiers, this is a global environment variable
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if (declaration && declaration.identifiers.length !== 0) {
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checkLocationAndReport(reference, declaration);
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}
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}
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});
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}
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/**
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* Validates variables inside of a node's scope.
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* @param {ASTNode} node The node to check.
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* @returns {void}
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* @private
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*/
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function findVariables() {
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var scope = context.getScope();
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findVariablesInScope(scope);
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}
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return {
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"Program": function() {
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var scope = context.getScope();
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findVariablesInScope(scope);
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// both Node.js and Modules have an extra scope
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if (context.ecmaFeatures.globalReturn || context.ecmaFeatures.modules) {
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findVariablesInScope(scope.childScopes[0]);
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}
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},
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"FunctionExpression": findVariables,
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"FunctionDeclaration": findVariables,
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"ArrowFunctionExpression": findVariables
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};
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};
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module.exports.schema = [
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{
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"enum": ["nofunc"]
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}
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];
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