JSLint - 声明变量的问题 [英] JSLint - problems declaring variables

问题描述

以下代码传递JSLint：

The following code passes JSLint:

var sGreeting = 'hello world';

switch (sGreeting)
{
case 'Hello world!':
    var a = 'some a value';
    break;
case 'Kamusta mundo!':
    var b = 'some b value';
    break;
case 'Salut le Monde!':
    var c = 'some c value';
    break;
default:
    break;
}

但是，一旦我将该代码放入函数中，JSLint就会抱怨我应该将...与前面的'var'语句结合使用。如果我遵循JSLint，我将定义可能永远不需要使用的变量。 我应该如何处理这个问题？以下是JSLint错误后面的代码：

However, once I put that code in a function, JSLint complains that I should Combine ... with the previous 'var' statement. If I follow JSLint, I would be defining variables that may never need to be used. How should I deal with this problem? Here's the code followed by JSLint's errors:

function foo()
{
    'use strict';
    var sGreeting = 'hello world';

    switch (sGreeting)
    {
    case 'Hello world!':
        var a = 'some a value';
        break;
    case 'Kamusta mundo!':
        var b = 'some b value';
        break;
    case 'Salut le Monde!':
        var c = 'some c value';
        break;
    default:
        break;
    }
}


Error:
Problem at line 9 character 7: Combine this with the previous 'var' statement.
var a = 'some a value';

Problem at line 12 character 7: Combine this with the previous 'var' statement.
var b = 'some b value';

Problem at line 15 character 7: Combine this with the previous 'var' statement.
var c = 'some c value';

推荐答案

javascript中唯一的范围是功能范围（括号做）不提供范围），所以switch语句中的那些vars正在悬挂到顶部功能。

The only scope in javascript is functional scope (braces do not provide scope), so those vars in the switch statement are being hoisted to the top of the function.

jslint建议的是：

What jslint is suggesting is this:

function foo() {
    'use strict';
    var a, b, c, sGreeting;

    sGreeting = 'hello world';

    switch (sGreeting) {
    case 'Hello world!':
        a = 'some a value';
        break;
    case 'Kamusta mundo!':
        b = 'some b value';
        break;
    case 'Salut le Monde!':
        c = 'some c value';
        break;
    default:
        break;
    }
}

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