no-empty-pattern
不允许空解构模式
在 配置文件 中使用来自 @eslint/js
的 recommended
配置可以启用此规则
使用解构时,可以创建没有效果的模式。当嵌入对象解构模式的右侧使用空大括号时,会发生这种情况,例如:
¥When using destructuring, it’s possible to create a pattern that has no effect. This happens when empty curly braces are used to the right of an embedded object destructuring pattern, such as:
// doesn't create any variables
var {a: {}} = foo;
在这段代码中,没有创建新变量,因为 a
只是一个位置助手,而 {}
应该包含要创建的变量,例如:
¥In this code, no new variables are created because a
is just a location helper while the {}
is expected to contain the variables to create, such as:
// creates variable b
var {a: { b }} = foo;
在许多情况下,空对象模式是作者打算使用默认值来代替的错误,例如:
¥In many cases, the empty object pattern is a mistake where the author intended to use a default value instead, such as:
// creates variable a
var {a = {}} = foo;
这两种模式之间的区别是微妙的,特别是因为有问题的空模式看起来就像一个对象字面量。
¥The difference between these two patterns is subtle, especially because the problematic empty pattern looks just like an object literal.
规则详情
¥Rule Details
此规则旨在标记解构对象和数组中的任何空模式,因此,只要遇到问题就会报告问题。
¥This rule aims to flag any empty patterns in destructured objects and arrays, and as such, will report a problem whenever one is encountered.
此规则的错误代码示例:
¥Examples of incorrect code for this rule:
/*eslint no-empty-pattern: "error"*/
var {} = foo;
var [] = foo;
var {a: {}} = foo;
var {a: []} = foo;
function foo({}) {}
function bar([]) {}
function baz({a: {}}) {}
function qux({a: []}) {}
此规则的正确代码示例:
¥Examples of correct code for this rule:
/*eslint no-empty-pattern: "error"*/
var {a = {}} = foo;
var {a = []} = foo;
function foo({a = {}}) {}
function bar({a = []}) {}
选项
¥Options
此规则有一个异常对象选项:
¥This rule has an object option for exceptions:
allowObjectPatternsAsParameters
默认设置为 false
。将此选项设置为 true
允许空对象模式作为函数参数。
¥Set to false
by default. Setting this option to true
allows empty object patterns as function parameters.
注意:此规则不允许空数组模式作为函数参数。
¥Note: This rule doesn’t allow empty array patterns as function parameters.
使用 {"allowObjectPatternsAsParameters": true}
选项的此规则的错误代码示例:
¥Examples of incorrect code for this rule with the {"allowObjectPatternsAsParameters": true}
option:
/*eslint no-empty-pattern: ["error", { "allowObjectPatternsAsParameters": true }]*/
function foo({a: {}}) {}
var bar = function({a: {}}) {};
var bar = ({a: {}}) => {};
var bar = ({} = bar) => {};
var bar = ({} = { bar: 1 }) => {};
function baz([]) {}
使用 {"allowObjectPatternsAsParameters": true}
选项的此规则的正确代码示例:
¥Examples of correct code for this rule with the {"allowObjectPatternsAsParameters": true}
option:
/*eslint no-empty-pattern: ["error", { "allowObjectPatternsAsParameters": true }]*/
function foo({}) {}
var bar = function({}) {};
var bar = ({}) => {};
function baz({} = {}) {}
版本
此规则是在 ESLint v1.7.0 中引入。