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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-duplicate-imports.js')
-rw-r--r-- | tools/node_modules/eslint/lib/rules/no-duplicate-imports.js | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-duplicate-imports.js b/tools/node_modules/eslint/lib/rules/no-duplicate-imports.js new file mode 100644 index 0000000000..d12c3a56df --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/no-duplicate-imports.js @@ -0,0 +1,137 @@ +/** + * @fileoverview Restrict usage of duplicate imports. + * @author Simen Bekkhus + */ +"use strict"; + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +/** + * Returns the name of the module imported or re-exported. + * + * @param {ASTNode} node - A node to get. + * @returns {string} the name of the module, or empty string if no name. + */ +function getValue(node) { + if (node && node.source && node.source.value) { + return node.source.value.trim(); + } + + return ""; +} + +/** + * Checks if the name of the import or export exists in the given array, and reports if so. + * + * @param {RuleContext} context - The ESLint rule context object. + * @param {ASTNode} node - A node to get. + * @param {string} value - The name of the imported or exported module. + * @param {string[]} array - The array containing other imports or exports in the file. + * @param {string} message - A message to be reported after the name of the module + * + * @returns {void} No return value + */ +function checkAndReport(context, node, value, array, message) { + if (array.indexOf(value) !== -1) { + context.report({ + node, + message: "'{{module}}' {{message}}", + data: { + module: value, + message + } + }); + } +} + +/** + * @callback nodeCallback + * @param {ASTNode} node - A node to handle. + */ + +/** + * Returns a function handling the imports of a given file + * + * @param {RuleContext} context - The ESLint rule context object. + * @param {boolean} includeExports - Whether or not to check for exports in addition to imports. + * @param {string[]} importsInFile - The array containing other imports in the file. + * @param {string[]} exportsInFile - The array containing other exports in the file. + * + * @returns {nodeCallback} A function passed to ESLint to handle the statement. + */ +function handleImports(context, includeExports, importsInFile, exportsInFile) { + return function(node) { + const value = getValue(node); + + if (value) { + checkAndReport(context, node, value, importsInFile, "import is duplicated."); + + if (includeExports) { + checkAndReport(context, node, value, exportsInFile, "import is duplicated as export."); + } + + importsInFile.push(value); + } + }; +} + +/** + * Returns a function handling the exports of a given file + * + * @param {RuleContext} context - The ESLint rule context object. + * @param {string[]} importsInFile - The array containing other imports in the file. + * @param {string[]} exportsInFile - The array containing other exports in the file. + * + * @returns {nodeCallback} A function passed to ESLint to handle the statement. + */ +function handleExports(context, importsInFile, exportsInFile) { + return function(node) { + const value = getValue(node); + + if (value) { + checkAndReport(context, node, value, exportsInFile, "export is duplicated."); + checkAndReport(context, node, value, importsInFile, "export is duplicated as import."); + + exportsInFile.push(value); + } + }; +} + +module.exports = { + meta: { + docs: { + description: "disallow duplicate module imports", + category: "ECMAScript 6", + recommended: false + }, + + schema: [{ + type: "object", + properties: { + includeExports: { + type: "boolean" + } + }, + additionalProperties: false + }] + }, + + create(context) { + const includeExports = (context.options[0] || {}).includeExports, + importsInFile = [], + exportsInFile = []; + + const handlers = { + ImportDeclaration: handleImports(context, includeExports, importsInFile, exportsInFile) + }; + + if (includeExports) { + handlers.ExportNamedDeclaration = handleExports(context, importsInFile, exportsInFile); + handlers.ExportAllDeclaration = handleExports(context, importsInFile, exportsInFile); + } + + return handlers; + } +}; |