forked from zhurui/management
103 lines
3.1 KiB
JavaScript
103 lines
3.1 KiB
JavaScript
/**
|
|
* @fileoverview Rule to flag when the same variable is declared more then once.
|
|
* @author Ilya Volodin
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
module.exports = {
|
|
meta: {
|
|
docs: {
|
|
description: "disallow variable redeclaration",
|
|
category: "Best Practices",
|
|
recommended: true,
|
|
url: "https://eslint.org/docs/rules/no-redeclare"
|
|
},
|
|
|
|
schema: [
|
|
{
|
|
type: "object",
|
|
properties: {
|
|
builtinGlobals: { type: "boolean" }
|
|
},
|
|
additionalProperties: false
|
|
}
|
|
]
|
|
},
|
|
|
|
create(context) {
|
|
const options = {
|
|
builtinGlobals: Boolean(context.options[0] && context.options[0].builtinGlobals)
|
|
};
|
|
|
|
/**
|
|
* Find variables in a given scope and flag redeclared ones.
|
|
* @param {Scope} scope - An eslint-scope scope object.
|
|
* @returns {void}
|
|
* @private
|
|
*/
|
|
function findVariablesInScope(scope) {
|
|
scope.variables.forEach(variable => {
|
|
const hasBuiltin = options.builtinGlobals && "writeable" in variable;
|
|
const count = (hasBuiltin ? 1 : 0) + variable.identifiers.length;
|
|
|
|
if (count >= 2) {
|
|
variable.identifiers.sort((a, b) => a.range[1] - b.range[1]);
|
|
|
|
for (let i = (hasBuiltin ? 0 : 1), l = variable.identifiers.length; i < l; i++) {
|
|
context.report({ node: variable.identifiers[i], message: "'{{a}}' is already defined.", data: { a: variable.name } });
|
|
}
|
|
}
|
|
});
|
|
|
|
}
|
|
|
|
/**
|
|
* Find variables in the current scope.
|
|
* @param {ASTNode} node - The Program node.
|
|
* @returns {void}
|
|
* @private
|
|
*/
|
|
function checkForGlobal(node) {
|
|
const scope = context.getScope(),
|
|
parserOptions = context.parserOptions,
|
|
ecmaFeatures = parserOptions.ecmaFeatures || {};
|
|
|
|
// Nodejs env or modules has a special scope.
|
|
if (ecmaFeatures.globalReturn || node.sourceType === "module") {
|
|
findVariablesInScope(scope.childScopes[0]);
|
|
} else {
|
|
findVariablesInScope(scope);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Find variables in the current scope.
|
|
* @returns {void}
|
|
* @private
|
|
*/
|
|
function checkForBlock() {
|
|
findVariablesInScope(context.getScope());
|
|
}
|
|
|
|
if (context.parserOptions.ecmaVersion >= 6) {
|
|
return {
|
|
Program: checkForGlobal,
|
|
BlockStatement: checkForBlock,
|
|
SwitchStatement: checkForBlock
|
|
};
|
|
}
|
|
return {
|
|
Program: checkForGlobal,
|
|
FunctionDeclaration: checkForBlock,
|
|
FunctionExpression: checkForBlock,
|
|
ArrowFunctionExpression: checkForBlock
|
|
};
|
|
|
|
}
|
|
};
|