72 lines
1.8 KiB
JavaScript
72 lines
1.8 KiB
JavaScript
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'use strict';
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const {isEmptyNode} = require('./ast/index.js');
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const getSwitchCaseHeadLocation = require('./utils/get-switch-case-head-location.js');
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const MESSAGE_ID_ERROR = 'no-useless-switch-case/error';
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const MESSAGE_ID_SUGGESTION = 'no-useless-switch-case/suggestion';
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const messages = {
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[MESSAGE_ID_ERROR]: 'Useless case in switch statement.',
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[MESSAGE_ID_SUGGESTION]: 'Remove this case.',
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};
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const isEmptySwitchCase = node => node.consequent.every(node => isEmptyNode(node));
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/** @param {import('eslint').Rule.RuleContext} context */
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const create = context => ({
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* 'SwitchStatement[cases.length>1]'(switchStatement) {
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const {cases} = switchStatement;
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// TypeScript allows multiple `default` cases
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const defaultCases = cases.filter(switchCase => switchCase.test === null);
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if (defaultCases.length !== 1) {
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return;
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}
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const [defaultCase] = defaultCases;
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// We only check cases where the last case is the `default` case
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if (defaultCase !== cases[cases.length - 1]) {
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return;
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}
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const uselessCases = [];
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for (let index = cases.length - 2; index >= 0; index--) {
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const node = cases[index];
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if (isEmptySwitchCase(node)) {
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uselessCases.unshift(node);
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} else {
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break;
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}
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}
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for (const node of uselessCases) {
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yield {
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node,
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loc: getSwitchCaseHeadLocation(node, context.getSourceCode()),
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messageId: MESSAGE_ID_ERROR,
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suggest: [
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{
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messageId: MESSAGE_ID_SUGGESTION,
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/** @param {import('eslint').Rule.RuleFixer} fixer */
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fix: fixer => fixer.remove(node),
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},
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],
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};
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}
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},
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});
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/** @type {import('eslint').Rule.RuleModule} */
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module.exports = {
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create,
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meta: {
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type: 'suggestion',
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docs: {
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description: 'Disallow useless case in switch statements.',
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},
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hasSuggestions: true,
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messages,
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},
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};
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