Disallow return before else (no-else-return)
禁止在 else 前有 return (no-else-return)
The --fix
option on the command line can automatically fix some of the problems reported by this rule.
命令行中的 --fix
选项可以自动修复一些该规则报告的问题。
If an if
block contains a return
statement, the else
block becomes unnecessary. Its contents can be placed outside of the block.
如果 if
块中包含了一个 return
语句,else
块就成了多余的了。可以将其内容移至块外。
function foo() {
if (x) {
return y;
} else {
return z;
}
}
Rule Details
This rule is aimed at highlighting an unnecessary block of code following an if
containing a return statement. As such, it will warn when it encounters an else
following a chain of if
s, all of them containing a return
statement.
该规则旨在突出含有 return 语句的 if
语句后的不必要的代码。因此,当else
语句出现在含有 return 语句的 if
语句之后,该规则将发出警告。
Options
This rule has an object option:
该规则有一个对象选项:
allowElseIf: true
(default) allowselse if
blocks after a returnallowElseIf: true
(默认) 允许在 return 之后有else if
块allowElseIf: false
disallowselse if
blocks after a returnallowElseIf: false
禁止在 return 之后有else if
块
allowElseIf: true
Examples of incorrect code for this rule:
错误 代码示例:
/*eslint no-else-return: "error"*/
function foo() {
if (x) {
return y;
} else {
return z;
}
}
function foo() {
if (x) {
return y;
} else if (z) {
return w;
} else {
return t;
}
}
function foo() {
if (x) {
return y;
} else {
var t = "foo";
}
return t;
}
function foo() {
if (error) {
return 'It failed';
} else {
if (loading) {
return "It's still loading";
}
}
}
// Two warnings for nested occurrences
function foo() {
if (x) {
if (y) {
return y;
} else {
return x;
}
} else {
return z;
}
}
Examples of correct code for this rule:
正确 代码示例:
/*eslint no-else-return: "error"*/
function foo() {
if (x) {
return y;
}
return z;
}
function foo() {
if (x) {
return y;
} else if (z) {
var t = "foo";
} else {
return w;
}
}
function foo() {
if (x) {
if (z) {
return y;
}
} else {
return z;
}
}
function foo() {
if (error) {
return 'It failed';
} else if (loading) {
return "It's still loading";
}
}
allowElseIf: false
Examples of incorrect code for this rule:
错误 代码示例:
/*eslint no-else-return: ["error", {allowElseIf: false}]*/
function foo() {
if (error) {
return 'It failed';
} else if (loading) {
return "It's still loading";
}
}
Examples of correct code for this rule:
正确 代码示例:
/*eslint no-else-return: ["error", {allowElseIf: false}]*/
function foo() {
if (error) {
return 'It failed';
}
if (loading) {
return "It's still loading";
}
}
Version
This rule was introduced in ESLint 0.0.9.
该规则在 ESLint 0.0.9 中被引入。