disallow confusing multiline expressions (no-unexpected-multiline)

禁止使用令人困惑的多行表达式 (no-unexpected-multiline)

Semicolons are usually optional in JavaScript, because of automatic semicolon insertion (ASI). You can require or disallow semicolons with the semi rule.

在 JavaScript 中,分号通常是可选的,因为会自动插入分号(ASI)。你可以使用 semi 规则要求或禁止分号。

The rules for ASI are relatively straightforward: As once described by Isaac Schlueter, a newline character always ends a statement, just like a semicolon, except where one of the following is true:

ASI 的规则是相对简单的:正如 Isaac Schlueter 曾经描述的那样,一个 \n 字符总是一个语句的结尾(像分号一样),除非下面之一为真:

In the exceptions where a newline does not end a statement, a typing mistake to omit a semicolon causes two unrelated consecutive lines to be interpreted as one expression. Especially for a coding style without semicolons, readers might overlook the mistake. Although syntactically correct, the code might throw exceptions when it is executed.


Rule Details

This rule disallows confusing multiline expressions where a newline looks like it is ending a statement, but is not.


Examples of incorrect code for this rule:

错误 代码示例:

/*eslint no-unexpected-multiline: "error"*/

var foo = bar
(1 || 2).baz();

var hello = 'world'
[1, 2, 3].forEach(addNumber);

let x = function() {}

let x = function() {}

let x = foo

Examples of correct code for this rule:

正确 代码示例:

/*eslint no-unexpected-multiline: "error"*/

var foo = bar;
(1 || 2).baz();

var foo = bar
;(1 || 2).baz()

var hello = 'world';
[1, 2, 3].forEach(addNumber);

var hello = 'world'
void [1, 2, 3].forEach(addNumber);

let x = function() {};

let tag = function() {}
tag `hello`

When Not To Use It

You can turn this rule off if you are confident that you will not accidentally introduce code like this.


Note that the patterns considered problems are not flagged by the semi rule.

注意,被认为有问题的模式 semi 规则标记。


This rule was introduced in ESLint 0.24.0.

该规则在 ESLint 0.24.0 中被引入。