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| 1 | +/** |
| 2 | + * @author Wayne Zhang |
| 3 | + * See LICENSE file in root directory for full license. |
| 4 | + */ |
| 5 | +'use strict' |
| 6 | + |
| 7 | +const utils = require('../utils') |
| 8 | + |
| 9 | +/** |
| 10 | + * @typedef { VDirective & { value: (VExpressionContainer & { expression: Expression | null } ) | null } } VIfDirective |
| 11 | + */ |
| 12 | + |
| 13 | +/** |
| 14 | + * @param {Expression} expression |
| 15 | + * @returns {boolean} |
| 16 | + */ |
| 17 | +function isNegatedExpression(expression) { |
| 18 | + return ( |
| 19 | + (expression.type === 'UnaryExpression' && expression.operator === '!') || |
| 20 | + (expression.type === 'BinaryExpression' && |
| 21 | + (expression.operator === '!=' || expression.operator === '!==')) |
| 22 | + ) |
| 23 | +} |
| 24 | + |
| 25 | +/** |
| 26 | + * @param {VElement} node |
| 27 | + * @returns {VElement|null} |
| 28 | + */ |
| 29 | +function getNextSibling(node) { |
| 30 | + if (!node.parent?.children) { |
| 31 | + return null |
| 32 | + } |
| 33 | + |
| 34 | + const siblings = node.parent.children |
| 35 | + const currentIndex = siblings.indexOf(node) |
| 36 | + |
| 37 | + for (let i = currentIndex + 1; i < siblings.length; i++) { |
| 38 | + const sibling = siblings[i] |
| 39 | + if (sibling.type === 'VElement') { |
| 40 | + return sibling |
| 41 | + } |
| 42 | + } |
| 43 | + |
| 44 | + return null |
| 45 | +} |
| 46 | + |
| 47 | +/** |
| 48 | + * @param {VElement} element |
| 49 | + * @returns {boolean} |
| 50 | + */ |
| 51 | +function isDirectlyFollowedByElse(element) { |
| 52 | + const nextElement = getNextSibling(element) |
| 53 | + return nextElement ? utils.hasDirective(nextElement, 'else') : false |
| 54 | +} |
| 55 | + |
| 56 | +module.exports = { |
| 57 | + meta: { |
| 58 | + type: 'suggestion', |
| 59 | + docs: { |
| 60 | + description: 'disallow negated conditions in v-if/v-else', |
| 61 | + categories: undefined, |
| 62 | + url: 'https://eslint.vuejs.org/rules/no-negated-v-if-condition.html' |
| 63 | + }, |
| 64 | + fixable: null, |
| 65 | + hasSuggestions: true, |
| 66 | + schema: [], |
| 67 | + messages: { |
| 68 | + negatedCondition: 'Unexpected negated condition in v-if with v-else.', |
| 69 | + fixNegatedCondition: |
| 70 | + 'Convert to positive condition and swap if/else blocks.' |
| 71 | + } |
| 72 | + }, |
| 73 | + /** @param {RuleContext} context */ |
| 74 | + create(context) { |
| 75 | + const sourceCode = context.getSourceCode() |
| 76 | + const templateTokens = |
| 77 | + sourceCode.parserServices.getTemplateBodyTokenStore && |
| 78 | + sourceCode.parserServices.getTemplateBodyTokenStore() |
| 79 | + |
| 80 | + /** |
| 81 | + * @param {VIfDirective} node |
| 82 | + */ |
| 83 | + function checkNegatedCondition(node) { |
| 84 | + if (!node.value?.expression) { |
| 85 | + return |
| 86 | + } |
| 87 | + |
| 88 | + const expression = node.value.expression |
| 89 | + const element = node.parent.parent |
| 90 | + |
| 91 | + if ( |
| 92 | + !isNegatedExpression(expression) || |
| 93 | + !isDirectlyFollowedByElse(element) |
| 94 | + ) { |
| 95 | + return |
| 96 | + } |
| 97 | + |
| 98 | + const elseElement = getNextSibling(element) |
| 99 | + if (!elseElement) { |
| 100 | + return |
| 101 | + } |
| 102 | + |
| 103 | + context.report({ |
| 104 | + node: expression, |
| 105 | + messageId: 'negatedCondition', |
| 106 | + suggest: [ |
| 107 | + { |
| 108 | + messageId: 'fixNegatedCondition', |
| 109 | + *fix(fixer) { |
| 110 | + yield* convertNegatedCondition(fixer, expression) |
| 111 | + yield* swapElementContents(fixer, element, elseElement) |
| 112 | + } |
| 113 | + } |
| 114 | + ] |
| 115 | + }) |
| 116 | + } |
| 117 | + |
| 118 | + /** |
| 119 | + * @param {RuleFixer} fixer |
| 120 | + * @param {Expression} expression |
| 121 | + */ |
| 122 | + function* convertNegatedCondition(fixer, expression) { |
| 123 | + if ( |
| 124 | + expression.type === 'UnaryExpression' && |
| 125 | + expression.operator === '!' |
| 126 | + ) { |
| 127 | + const token = templateTokens.getFirstToken(expression) |
| 128 | + if (token?.type === 'Punctuator' && token.value === '!') { |
| 129 | + yield fixer.remove(token) |
| 130 | + } |
| 131 | + return |
| 132 | + } |
| 133 | + |
| 134 | + if (expression.type === 'BinaryExpression') { |
| 135 | + const operatorToken = templateTokens.getTokenAfter( |
| 136 | + expression.left, |
| 137 | + (token) => |
| 138 | + token?.type === 'Punctuator' && token.value === expression.operator |
| 139 | + ) |
| 140 | + |
| 141 | + if (!operatorToken) return |
| 142 | + |
| 143 | + if (expression.operator === '!=') { |
| 144 | + yield fixer.replaceText(operatorToken, '==') |
| 145 | + } else if (expression.operator === '!==') { |
| 146 | + yield fixer.replaceText(operatorToken, '===') |
| 147 | + } |
| 148 | + } |
| 149 | + } |
| 150 | + |
| 151 | + /** |
| 152 | + * @param {VElement} element |
| 153 | + * @returns {string} |
| 154 | + */ |
| 155 | + function getElementContent(element) { |
| 156 | + if (element.children.length === 0 || !element.endTag) { |
| 157 | + return '' |
| 158 | + } |
| 159 | + |
| 160 | + const contentStart = element.startTag.range[1] |
| 161 | + const contentEnd = element.endTag.range[0] |
| 162 | + |
| 163 | + return sourceCode.text.slice(contentStart, contentEnd) |
| 164 | + } |
| 165 | + |
| 166 | + /** |
| 167 | + * @param {RuleFixer} fixer |
| 168 | + * @param {VElement} ifElement |
| 169 | + * @param {VElement} elseElement |
| 170 | + */ |
| 171 | + function* swapElementContents(fixer, ifElement, elseElement) { |
| 172 | + if (!ifElement.endTag || !elseElement.endTag) { |
| 173 | + return |
| 174 | + } |
| 175 | + |
| 176 | + const ifContent = getElementContent(ifElement) |
| 177 | + const elseContent = getElementContent(elseElement) |
| 178 | + |
| 179 | + if (ifContent === elseContent) { |
| 180 | + return |
| 181 | + } |
| 182 | + |
| 183 | + yield fixer.replaceTextRange( |
| 184 | + [ifElement.startTag.range[1], ifElement.endTag.range[0]], |
| 185 | + elseContent |
| 186 | + ) |
| 187 | + yield fixer.replaceTextRange( |
| 188 | + [elseElement.startTag.range[1], elseElement.endTag.range[0]], |
| 189 | + ifContent |
| 190 | + ) |
| 191 | + } |
| 192 | + |
| 193 | + return utils.defineTemplateBodyVisitor(context, { |
| 194 | + /** @param {VIfDirective} node */ |
| 195 | + "VAttribute[directive=true][key.name.name='if']"(node) { |
| 196 | + checkNegatedCondition(node) |
| 197 | + }, |
| 198 | + /** @param {VIfDirective} node */ |
| 199 | + "VAttribute[directive=true][key.name.name='else-if']"(node) { |
| 200 | + checkNegatedCondition(node) |
| 201 | + } |
| 202 | + }) |
| 203 | + } |
| 204 | +} |
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