146 lines
4.4 KiB
JavaScript
146 lines
4.4 KiB
JavaScript
/**
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* @fileoverview Restrict usage of duplicate imports.
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* @author Simen Bekkhus
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/**
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* Returns the name of the module imported or re-exported.
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*
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* @param {ASTNode} node - A node to get.
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* @returns {string} the name of the module, or empty string if no name.
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*/
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function getValue(node) {
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if (node && node.source && node.source.value) {
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return node.source.value.trim();
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}
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return "";
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}
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/**
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* Checks if the name of the import or export exists in the given array, and reports if so.
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*
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* @param {RuleContext} context - The ESLint rule context object.
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* @param {ASTNode} node - A node to get.
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* @param {string} value - The name of the imported or exported module.
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* @param {string[]} array - The array containing other imports or exports in the file.
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* @param {string} messageId - A messageId to be reported after the name of the module
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*
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* @returns {void} No return value
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*/
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function checkAndReport(context, node, value, array, messageId) {
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if (array.indexOf(value) !== -1) {
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context.report({
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node,
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messageId,
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data: {
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module: value
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}
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});
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}
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}
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/**
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* @callback nodeCallback
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* @param {ASTNode} node - A node to handle.
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*/
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/**
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* Returns a function handling the imports of a given file
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*
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* @param {RuleContext} context - The ESLint rule context object.
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* @param {boolean} includeExports - Whether or not to check for exports in addition to imports.
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* @param {string[]} importsInFile - The array containing other imports in the file.
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* @param {string[]} exportsInFile - The array containing other exports in the file.
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*
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* @returns {nodeCallback} A function passed to ESLint to handle the statement.
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*/
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function handleImports(context, includeExports, importsInFile, exportsInFile) {
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return function(node) {
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const value = getValue(node);
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if (value) {
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checkAndReport(context, node, value, importsInFile, "import");
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if (includeExports) {
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checkAndReport(context, node, value, exportsInFile, "importAs");
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}
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importsInFile.push(value);
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}
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};
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}
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/**
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* Returns a function handling the exports of a given file
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*
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* @param {RuleContext} context - The ESLint rule context object.
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* @param {string[]} importsInFile - The array containing other imports in the file.
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* @param {string[]} exportsInFile - The array containing other exports in the file.
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*
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* @returns {nodeCallback} A function passed to ESLint to handle the statement.
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*/
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function handleExports(context, importsInFile, exportsInFile) {
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return function(node) {
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const value = getValue(node);
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if (value) {
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checkAndReport(context, node, value, exportsInFile, "export");
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checkAndReport(context, node, value, importsInFile, "exportAs");
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exportsInFile.push(value);
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}
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};
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}
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module.exports = {
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meta: {
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type: "problem",
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docs: {
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description: "disallow duplicate module imports",
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category: "ECMAScript 6",
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recommended: false,
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url: "https://eslint.org/docs/rules/no-duplicate-imports"
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},
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schema: [{
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type: "object",
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properties: {
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includeExports: {
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type: "boolean",
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default: false
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}
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},
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additionalProperties: false
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}],
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messages: {
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import: "'{{module}}' import is duplicated.",
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importAs: "'{{module}}' import is duplicated as export.",
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export: "'{{module}}' export is duplicated.",
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exportAs: "'{{module}}' export is duplicated as import."
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}
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},
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create(context) {
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const includeExports = (context.options[0] || {}).includeExports,
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importsInFile = [],
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exportsInFile = [];
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const handlers = {
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ImportDeclaration: handleImports(context, includeExports, importsInFile, exportsInFile)
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};
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if (includeExports) {
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handlers.ExportNamedDeclaration = handleExports(context, importsInFile, exportsInFile);
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handlers.ExportAllDeclaration = handleExports(context, importsInFile, exportsInFile);
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}
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return handlers;
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}
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};
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