/**
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* @fileoverview Don't introduce side effects in computed properties
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* @author Michał Sajnóg
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*/
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'use strict'
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const utils = require('../utils')
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/**
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* @typedef {import('../utils').VueObjectData} VueObjectData
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* @typedef {import('../utils').ComponentComputedProperty} ComponentComputedProperty
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*/
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// ------------------------------------------------------------------------------
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// Rule Definition
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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 side effects in computed properties',
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categories: ['vue3-essential', 'essential'],
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url:
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'https://eslint.vuejs.org/rules/no-side-effects-in-computed-properties.html'
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},
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fixable: null,
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schema: []
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},
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/** @param {RuleContext} context */
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create(context) {
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/** @type {Map<ObjectExpression, ComponentComputedProperty[]>} */
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const computedPropertiesMap = new Map()
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/**
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* @typedef {object} ScopeStack
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* @property {ScopeStack | null} upper
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* @property {BlockStatement | Expression | null} body
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*/
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/**
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* @type {ScopeStack | null}
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*/
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let scopeStack = null
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/** @param {FunctionExpression | ArrowFunctionExpression | FunctionDeclaration} node */
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function onFunctionEnter(node) {
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scopeStack = {
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upper: scopeStack,
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body: node.body
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}
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}
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function onFunctionExit() {
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scopeStack = scopeStack && scopeStack.upper
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}
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return utils.defineVueVisitor(context, {
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onVueObjectEnter(node) {
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computedPropertiesMap.set(node, utils.getComputedProperties(node))
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},
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':function': onFunctionEnter,
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':function:exit': onFunctionExit,
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/**
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* @param {(Identifier | ThisExpression) & {parent: MemberExpression}} node
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* @param {VueObjectData} data
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*/
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'MemberExpression > :matches(Identifier, ThisExpression)'(
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node,
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{ node: vueNode }
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) {
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if (!scopeStack) {
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return
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}
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const targetBody = scopeStack.body
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const computedProperty = /** @type {ComponentComputedProperty[]} */ (computedPropertiesMap.get(
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vueNode
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)).find((cp) => {
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return (
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cp.value &&
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node.loc.start.line >= cp.value.loc.start.line &&
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node.loc.end.line <= cp.value.loc.end.line &&
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targetBody === cp.value
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)
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})
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if (!computedProperty) {
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return
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}
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if (!utils.isThis(node, context)) {
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return
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}
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const mem = node.parent
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if (mem.object !== node) {
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return
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}
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const invalid = utils.findMutating(mem)
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if (invalid) {
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context.report({
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node: invalid.node,
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message: 'Unexpected side effect in "{{key}}" computed property.',
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data: { key: computedProperty.key || 'Unknown' }
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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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