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/**
* @fileoverview Don't introduce side effects in computed properties
* @author Michał Sajnóg
*/
'use strict'
const utils = require('../utils')
// ------------------------------------------------------------------------------
// Rule Definition
// ------------------------------------------------------------------------------
module.exports = {
meta: {
type: 'problem',
docs: {
description: 'disallow side effects in computed properties',
category: 'essential',
url: 'https://eslint.vuejs.org/rules/no-side-effects-in-computed-properties.html'
},
fixable: null,
schema: []
},
create (context) {
const forbiddenNodes = []
return Object.assign({},
{
// this.xxx <=|+=|-=>
'AssignmentExpression' (node) {
if (node.left.type !== 'MemberExpression') return
if (utils.parseMemberExpression(node.left)[0] === 'this') {
forbiddenNodes.push(node)
}
},
// this.xxx <++|-->
'UpdateExpression > MemberExpression' (node) {
if (utils.parseMemberExpression(node)[0] === 'this') {
forbiddenNodes.push(node)
}
},
// this.xxx.func()
'CallExpression' (node) {
const code = utils.parseMemberOrCallExpression(node)
const MUTATION_REGEX = /(this.)((?!(concat|slice|map|filter)\().)[^\)]*((push|pop|shift|unshift|reverse|splice|sort|copyWithin|fill)\()/g
if (MUTATION_REGEX.test(code)) {
forbiddenNodes.push(node)
}
}
},
utils.executeOnVue(context, (obj) => {
const computedProperties = utils.getComputedProperties(obj)
computedProperties.forEach(cp => {
forbiddenNodes.forEach(node => {
if (
cp.value &&
node.loc.start.line >= cp.value.loc.start.line &&
node.loc.end.line <= cp.value.loc.end.line
) {
context.report({
node: node,
message: 'Unexpected side effect in "{{key}}" computed property.',
data: { key: cp.key }
})
}
})
})
})
)
}
}