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  <div id="chatlog__message-container-402639880045461512" class="chatlog__message-container" data-message-id="402639880045461512">
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      <div class="chatlog__message-aside"><img class="chatlog__avatar" src="https://cdn.discordapp.com/avatars/293624673265123328/accd07acc220a18568ba46a6e9ede18a.png?size=512" alt="Avatar" loading="lazy"></div>
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        <div class="chatlog__header"><span class="chatlog__author" style="color:rgb(17,128,106)" title="koher" data-user-id="293624673265123328">koher</span> <a href="/channels/387857770038427648?category=main&amp;channel=testing&amp;message_id=402640856659787786"><span class="chatlog__timestamp" title="Tuesday, January 16, 2018 1:47 AM"></span></a><a href="#chatlog__message-container-402639880045461512">1/16/2018 1:47 AM</a></div>
        <div class="chatlog__content chatlog__markdown"><span class="chatlog__markdown-preserve">僕も昔はよく <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">Optional</code> の <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">map</code> や <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">flatMap</code> を使ってましたが、今はほとんど <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">guard let</code> 使ってます。可読性のために。 <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">?.</code> も必要最小限しか使わないですね。</span></div>
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  <div id="chatlog__message-container-402640517638389760" class="chatlog__message-container" data-message-id="402640517638389760">
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        <div class="chatlog__short-timestamp" title="Tuesday, January 16, 2018 1:49 AM">1:49 AM</div>
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        <div class="chatlog__content chatlog__markdown"><span class="chatlog__markdown-preserve">一方で、 Forced unwrapping は必要なケースでは（ <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">nil</code> になるのがロジックエラーなら）よく使います。できるだけ、それが <code class="chatlog__markdown-pre chatlog__markdown-pre--inline">nil</code> にならない理由をコメントをつけるようにしています（本当はコメントではなくエラーメッセージにしてくれるものがあれば標準であればいいですが）。</span></div>
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  <div id="chatlog__message-container-402640642205024256" class="chatlog__message-container" data-message-id="402640642205024256">
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        <div class="chatlog__short-timestamp" title="Tuesday, January 16, 2018 1:50 AM">1:50 AM</div>
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        <div class="chatlog__content chatlog__markdown"><span class="chatlog__markdown-preserve">ああ、 <span class="chatlog__markdown-mention">#testing</span> からずれてしまいました。</span></div>
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  <div id="chatlog__message-container-402640766305828865" class="chatlog__message-container" data-message-id="402640766305828865">
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        <div class="chatlog__short-timestamp" title="Tuesday, January 16, 2018 1:50 AM">1:50 AM</div>
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        <div class="chatlog__content chatlog__markdown"><span class="chatlog__markdown-preserve"><code class="chatlog__markdown-pre chatlog__markdown-pre--inline">!</code> を含むロジックエラーは Swift でテストできないのが難点ですね。</span></div>
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  <div id="chatlog__message-container-402640856659787786" class="chatlog__message-container" data-message-id="402640856659787786">
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        <div class="chatlog__short-timestamp" title="Tuesday, January 16, 2018 1:51 AM">1:51 AM</div>
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        <div class="chatlog__content chatlog__markdown"><span class="chatlog__markdown-preserve"><code class="chatlog__markdown-pre chatlog__markdown-pre--inline">precondition</code> に引っかかることをテストしたいこととか結構よくあります・・・。</span></div>
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