blocks|key|125499|text|避免错误的一种方法(没有真正修复它，但至少不会崩溃)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|125500|$scope.fav+=+JSON.parse(localStorage["fav"]+%7C%7C+'[]');|code-block|syntax|javascript|125501|因为localStorage["fav"]是undefined，所以你会得到这个错误。|offset|length|style|CODE|125502|试试这个，你就会自己明白了：|125503|var+a+=+undefined;
JSON.parse(a);|125504|entityMap^0|0|0|2|J|M|9|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

One way to avoid the error (not really fixing it, but at least won't break):

<pre><code>$scope.fav = JSON.parse(localStorage["fav"] || '[]');
</code></pre>

You're getting that error because <code>localStorage["fav"]</code> is <code>undefined</code>.

Try this and you'll understand all by yourself:

<pre><code>var a = undefined;
JSON.parse(a);
</code></pre>

blocks|key|125546|text|Unexpected+token:+u几乎总是源于试图解析一个为undefined的值。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|125547|你可以像这样防止它：|125548|if+(localStorage['fav'])+{
++$scope.fav+=+JSON.parse(localStorage['fav'];
}|code-block|syntax|javascript|125549|entityMap^0|0|J|W|9|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

<code>Unexpected token: u</code> almost always stems from trying to parse a value that is <code>undefined</code>.

You can guard against that like this:

<pre><code>if (localStorage['fav']) {
 $scope.fav = JSON.parse(localStorage['fav'];
}
</code></pre>

blocks|key|125608|text|根据您更新的问题，if条件没有意义，因为您在前面将$scope.fav设置为[]，因此它永远不可能为"undefined"。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|125609|最有可能的情况是，您的测试是这样的：|125610|if+(typeof+localStorage["fav"]+!==+"undefined")+{
++$scope.fav+=+JSON.parse(localStorage["fav"]);
}|code-block|syntax|javascript|125611|由于我不知道是否存在localStorage["fav"]可能包含字符串"undefined"的情况，因此您可能也需要为此进行测试。|125612|if+(typeof+localStorage["fav"]+!==+"undefined"
++++&&+localStorage["fav"]+!==+"undefined")+{
++$scope.fav+=+JSON.parse(localStorage["fav"]);
}|125613|entityMap^0|9|2|P|A|12|2|1E|B|0|0|0|A|J|10|B|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|19|8|@]|D|@]|E|$]]]|R|$]]

Base on your updated question the <code>if</code> condition does not make sense, because you set <code>$scope.fav</code> to <code>[]</code> right before, so it can never be <code>"undefined"</code>.

Most likely you want to have your test that way:

<pre><code>if (typeof localStorage["fav"] !== "undefined") {
 $scope.fav = JSON.parse(localStorage["fav"]);
}
</code></pre>

As i don't know if there is a situation where <code>localStorage["fav"]</code> could contain the string <code>"undefined"</code> you probably also need test for this.

<pre><code>if (typeof localStorage["fav"] !== "undefined"
 &amp;&amp; localStorage["fav"] !== "undefined") {
 $scope.fav = JSON.parse(localStorage["fav"]);
}
</code></pre>

blocks|key|4631732|text|在我的例子中，问题是我得到的值是localStorage.getItem[key]，而它应该是localStorage.getItem(key)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4631733|上面的答案已经更好地解释了剩下的和通常面临的问题。|4631734|entityMap^0|G|P|1B|P|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|-4|5|6|7|P|8|@]|D|@]|E|$]]]|I|$]]

In my case, the problem was I was getting the value as <code>localStorage.getItem[key]</code> whereas it should have been <code>localStorage.getItem(key)</code>.

The rest and normally faced issues have been better explained already by the above answers.

I have read online that the unexpected token u issue can come from using JSON.parse(). On my iPhone 5 there is no problem, but on my Nexus 7 I get this sequence of errors:

<img src="https://i.stack.imgur.com/AkUJ7.png" alt="enter image description here">
<a href="https://i.stack.imgur.com/AkUJ7.png" rel="noreferrer">View large</a>

I realize this is a duplicate, but I am not sure how to solve this for my specific problem. Here is where I implement JSON.parse()

<pre><code> $scope.fav = []; 

if ($scope.fav !== 'undefined') {
 $scope.fav = JSON.parse(localStorage["fav"]);
}
</code></pre>

Unexpected token: u JSON.parse() issue

JSON

我在网上读到，意外的token u问题可能来自于使用JSON.parse()。在我的iPhone 5上没有问题，但在我的Nexus7上我得到了以下错误序列：​我意识到这是一个复制品，但我不确定如何解决我的特定问题。下面是我实现JSON.parse()的地方 $scope.fav = []; if ($scope.fav...

问意外的令牌:u JSON.parse()问题
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