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                                <h1 id="&#xBAA9;&#xCC28;-table-of-contents">&#xBAA9;&#xCC28; (Table of Contents)</h1>
<ol>
<li><a href="#&#xC18C;&#xAC1C;-introduction">&#xC18C;&#xAC1C; (Introduction)</a></li>
<li><a href="#&#xBD88;&#xB9AC;&#xC5B8;-boolean">&#xBD88;&#xB9AC;&#xC5B8; (Boolean)</a></li>
<li><a href="#&#xC22B;&#xC790;-number">&#xC22B;&#xC790; (Number)</a></li>
<li><a href="#&#xBB38;&#xC790;&#xC5F4;-string">&#xBB38;&#xC790;&#xC5F4; (String)</a></li>
<li><a href="#&#xBC30;&#xC5F4;-array">&#xBC30;&#xC5F4; (Array)</a></li>
<li><a href="#&#xD29C;&#xD50C;-tuple">&#xD29C;&#xD50C; (Tuple)</a></li>
<li><a href="#&#xC5F4;&#xAC70;-enum">&#xC5F4;&#xAC70; (Enum)</a></li>
<li><a href="#any">Any</a></li>
<li><a href="#void">Void</a></li>
<li><a href="#null-and-undefined">Null and Undefined</a></li>
<li><a href="#never">Never</a></li>
<li><a href="#&#xAC1D;&#xCCB4;-object">&#xAC1D;&#xCCB4; (Object)</a></li>
<li><a href="#&#xD0C0;&#xC785;-&#xB2E8;&#xC5B8;-type-assertions">&#xD0C0;&#xC785; &#xB2E8;&#xC5B8; (Type assertions)</a></li>
<li><a href="#let&#xC5D0;-&#xAD00;&#xD558;&#xC5EC;">&apos;let&apos;&#xC5D0; &#xAD00;&#xD558;&#xC5EC;</a></li>
</ol>
<h1 id="&#xC18C;&#xAC1C;-introduction">&#xC18C;&#xAC1C; (Introduction)</h1>
<p>&#xD504;&#xB85C;&#xADF8;&#xB7A8;&#xC774; &#xC720;&#xC6A9;&#xD558;&#xB824;&#xBA74; &#xC22B;&#xC790;, &#xBB38;&#xC790;&#xC5F4;, &#xAD6C;&#xC870;&#xCCB4;, &#xBD88;&#xB9AC;&#xC5B8; &#xAC12;&#xACFC; &#xAC19;&#xC740; &#xAC04;&#xB2E8;&#xD55C; &#xB370;&#xC774;&#xD130; &#xB2E8;&#xC704;&#xAC00; &#xD544;&#xC694;&#xD569;&#xB2C8;&#xB2E4;.
TypeScript&#xB294; JavaScript&#xC640; &#xAC70;&#xC758; &#xB3D9;&#xC77C;&#xD55C; &#xB370;&#xC774;&#xD130; &#xD0C0;&#xC785;&#xC744; &#xC9C0;&#xC6D0;&#xD558;&#xBA70;, &#xC5F4;&#xAC70; &#xD0C0;&#xC785;&#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xC5EC; &#xB354; &#xD3B8;&#xB9AC;&#xD558;&#xAC8C; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<h1 id="&#xBD88;&#xB9AC;&#xC5B8;-boolean">&#xBD88;&#xB9AC;&#xC5B8; (Boolean)</h1>
<p>&#xAC00;&#xC7A5; &#xAE30;&#xBCF8;&#xC801;&#xC778; &#xB370;&#xC774;&#xD130; &#xD0C0;&#xC785;&#xC740; JavaScript, TypeScript&#xC5D0;&#xC11C; <code>boolean</code> &#xAC12;&#xC774;&#xB77C;&#xACE0; &#xC77C;&#xCEEB;&#xB294; &#xCC38;/&#xAC70;&#xC9D3;(true/false) &#xAC12;&#xC785;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">isDone</span>: <span class="cm-variable-3">boolean</span> <span class="cm-operator">=</span> <span class="cm-atom">false</span>;
</code></pre>
<h1 id="&#xC22B;&#xC790;-number">&#xC22B;&#xC790; (Number)</h1>
<p>JavaScript&#xCC98;&#xB7FC;, TypeScript&#xC758; &#xBAA8;&#xB4E0; &#xC22B;&#xC790;&#xB294; &#xBD80;&#xB3D9; &#xC18C;&#xC218; &#xAC12;&#xC785;&#xB2C8;&#xB2E4;.
&#xBD80;&#xB3D9; &#xC18C;&#xC218;&#xC5D0;&#xB294; <code>number</code>&#xB77C;&#xB294; &#xD0C0;&#xC785;&#xC774; &#xBD99;&#xD600;&#xC9D1;&#xB2C8;&#xB2E4;.
TypeScript&#xB294; 16&#xC9C4;&#xC218;, 10&#xC9C4;&#xC218; &#xB9AC;&#xD130;&#xB7F4;&#xC5D0; &#xB354;&#xBD88;&#xC5B4;, ECMAScript 2015&#xC5D0; &#xC18C;&#xAC1C;&#xB41C; 2&#xC9C4;&#xC218;, 8&#xC9C4;&#xC218; &#xB9AC;&#xD130;&#xB7F4;&#xB3C4; &#xC9C0;&#xC6D0;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">decimal</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> <span class="cm-number">6</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">hex</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> <span class="cm-number">0xf00d</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">binary</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> <span class="cm-number">0</span><span class="cm-variable">b1010</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">octal</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> <span class="cm-number">0</span><span class="cm-variable">o744</span>;
</code></pre>
<h1 id="&#xBB38;&#xC790;&#xC5F4;-string">&#xBB38;&#xC790;&#xC5F4; (String)</h1>
<p>&#xC6F9; &#xD398;&#xC774;&#xC9C0;, &#xC11C;&#xBC84; &#xAC19;&#xC740; &#xD504;&#xB85C;&#xADF8;&#xB7A8;&#xC744; JavaScript&#xB85C; &#xB9CC;&#xB4E4; &#xB54C; &#xAE30;&#xBCF8;&#xC801;&#xC73C;&#xB85C; &#xD14D;&#xC2A4;&#xD2B8; &#xB370;&#xC774;&#xD130;&#xB97C; &#xB2E4;&#xB8E8;&#xB294; &#xC791;&#xC5C5;&#xC774; &#xD544;&#xC694;&#xD569;&#xB2C8;&#xB2E4;.
&#xB2E4;&#xB978; &#xC5B8;&#xC5B4;&#xB4E4;&#xCC98;&#xB7FC;, TypeScript&#xC5D0;&#xC11C;&#xB294; &#xD14D;&#xC2A4;&#xD2B8; &#xB370;&#xC774;&#xD130; &#xD0C0;&#xC785;&#xC744; <code>string</code>&#xC73C;&#xB85C; &#xD45C;&#xD604;&#xD569;&#xB2C8;&#xB2E4;.
JavaScript&#xCC98;&#xB7FC; TypeScript&#xB3C4; &#xD070;&#xB530;&#xC634;&#xD45C; (<code>&quot;</code>)&#xB098; &#xC791;&#xC740;&#xB530;&#xC634;&#xD45C; (<code>&apos;</code>)&#xB97C; &#xBB38;&#xC790;&#xC5F4; &#xB370;&#xC774;&#xD130;&#xB97C; &#xAC10;&#xC2F8;&#xB294;&#xB370; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">color</span>: <span class="cm-variable-3">string</span> <span class="cm-operator">=</span> <span class="cm-string">&quot;blue&quot;</span>;
<span class="cm-variable">color</span> <span class="cm-operator">=</span> <span class="cm-string">&apos;red&apos;</span>;
</code></pre>
<p>&#xB610;&#xD55C; <em>&#xD15C;&#xD50C;&#xB9BF; &#xBB38;&#xC790;&#xC5F4;</em> &#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xBA74; &#xC5EC;&#xB7EC; &#xC904;&#xC5D0; &#xAC78;&#xCCD0; &#xBB38;&#xC790;&#xC5F4;&#xC744; &#xC791;&#xC131;&#xD560; &#xC218; &#xC788;&#xC73C;&#xBA70;, &#xD45C;&#xD604;&#xC2DD;&#xC744; &#xD3EC;&#xD568;&#xC2DC;&#xD0AC; &#xC218;&#xB3C4; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774; &#xBB38;&#xC790;&#xC5F4;&#xC740; &#xBC31;&#xD2F1;/&#xBC31;&#xCFFC;&#xD2B8; (<code>` </code>) &#xBB38;&#xC790;&#xB85C; &#xAC10;&#xC2F8;&#xC9C0;&#xBA70;, <code>${ expr }</code>&#xACFC; &#xAC19;&#xC740; &#xD615;&#xD0DC;&#xB85C; &#xD45C;&#xD604;&#xC2DD;&#xC744; &#xD3EC;&#xD568;&#xC2DC;&#xD0AC; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">fullName</span>: <span class="cm-variable-3">string</span> <span class="cm-operator">=</span> <span class="cm-string-2">`Bob Bobbington`</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">age</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> <span class="cm-number">37</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">sentence</span>: <span class="cm-variable-3">string</span> <span class="cm-operator">=</span> <span class="cm-string-2">`Hello, my name is ${</span> <span class="cm-variable">fullName</span> <span class="cm-string-2">}</span><span class="cm-string-2">.</span>
<span class="cm-string-2">I&apos;ll be ${</span> <span class="cm-variable">age</span> <span class="cm-operator">+</span> <span class="cm-number">1</span> <span class="cm-string-2">}</span> <span class="cm-string-2">years old next month.`</span>;
</code></pre>
<p>&#xC704;&#xB294; &#xC544;&#xB798; <code>sentence</code>&#xC120;&#xC5B8;&#xACFC; &#xB3D9;&#xC77C;&#xD569;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">sentence</span>: <span class="cm-variable-3">string</span> <span class="cm-operator">=</span> <span class="cm-string">&quot;Hello, my name is &quot;</span> <span class="cm-operator">+</span> <span class="cm-variable">fullName</span> <span class="cm-operator">+</span> <span class="cm-string">&quot;.\n\n&quot;</span> <span class="cm-operator">+</span>
    <span class="cm-string">&quot;I&apos;ll be &quot;</span> <span class="cm-operator">+</span> (<span class="cm-variable">age</span> <span class="cm-operator">+</span> <span class="cm-number">1</span>) <span class="cm-operator">+</span> <span class="cm-string">&quot; years old next month.&quot;</span>;
</code></pre>
<h1 id="&#xBC30;&#xC5F4;-array">&#xBC30;&#xC5F4; (Array)</h1>
<p>TypeScript&#xB294; JavaScript&#xCC98;&#xB7FC; &#xAC12;&#xB4E4;&#xC744; &#xBC30;&#xC5F4;&#xB85C; &#xB2E4;&#xB8F0; &#xC218; &#xC788;&#xAC8C; &#xD574;&#xC90D;&#xB2C8;&#xB2E4;.
&#xBC30;&#xC5F4; &#xD0C0;&#xC785;&#xC740; &#xB450; &#xAC00;&#xC9C0; &#xBC29;&#xBC95;&#xC73C;&#xB85C; &#xC4F8; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xCCAB; &#xBC88;&#xC9F8; &#xBC29;&#xBC95;&#xC740;, &#xBC30;&#xC5F4; &#xC694;&#xC18C;&#xB4E4;&#xC744; &#xB098;&#xD0C0;&#xB0B4;&#xB294; &#xD0C0;&#xC785; &#xB4A4;&#xC5D0; <code>[]</code>&#xB97C; &#xC4F0;&#xB294; &#xAC83;&#xC785;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">list</span>: <span class="cm-variable-3">number</span>[] <span class="cm-operator">=</span> [<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>];
</code></pre>
<p>&#xB450; &#xBC88;&#xC9F8; &#xBC29;&#xBC95;&#xC740; &#xC81C;&#xB124;&#xB9AD; &#xBC30;&#xC5F4; &#xD0C0;&#xC785;&#xC744; &#xC4F0;&#xB294; &#xAC83;&#xC785;&#xB2C8;&#xB2E4;. <code>Array&lt;elemType&gt;</code>:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">list</span>: <span class="cm-variable-3">Array</span><span class="cm-operator">&lt;</span><span class="cm-variable-3">number</span><span class="cm-operator">&gt;</span> <span class="cm-operator">=</span> [<span class="cm-number">1</span>, <span class="cm-number">2</span>, <span class="cm-number">3</span>];
</code></pre>
<h1 id="&#xD29C;&#xD50C;-tuple">&#xD29C;&#xD50C; (Tuple)</h1>
<p>&#xD29C;&#xD50C; &#xD0C0;&#xC785;&#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xBA74;, &#xC694;&#xC18C;&#xC758; &#xD0C0;&#xC785;&#xACFC; &#xAC1C;&#xC218;&#xAC00; &#xACE0;&#xC815;&#xB41C; &#xBC30;&#xC5F4;&#xC744; &#xD45C;&#xD604;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;. &#xB2E8; &#xC694;&#xC18C;&#xB4E4;&#xC758; &#xD0C0;&#xC785;&#xC774; &#xBAA8;&#xB450; &#xAC19;&#xC744; &#xD544;&#xC694;&#xB294; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;. &#xC608;&#xB97C; &#xB4E4;&#xC5B4;, <code>number</code>, <code>string</code> &#xC774; &#xC30D;&#xC73C;&#xB85C; &#xC788;&#xB294; &#xAC12;&#xC744; &#xB098;&#xD0C0;&#xB0B4;&#xACE0; &#xC2F6;&#xC744; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-comment">// &#xD29C;&#xD50C; &#xD0C0;&#xC785;&#xC73C;&#xB85C; &#xC120;&#xC5B8;</span>
<span class="cm-keyword">let</span> <span class="cm-variable">x</span>: [<span class="cm-variable-3">string</span>, <span class="cm-variable-3">number</span>];
<span class="cm-comment">// &#xCD08;&#xAE30;&#xD654;</span>
<span class="cm-variable">x</span> <span class="cm-operator">=</span> [<span class="cm-string">&quot;hello&quot;</span>, <span class="cm-number">10</span>]; <span class="cm-comment">// &#xC131;&#xACF5;</span>
<span class="cm-comment">// &#xC798;&#xBABB;&#xB41C; &#xCD08;&#xAE30;&#xD654;</span>
<span class="cm-variable">x</span> <span class="cm-operator">=</span> [<span class="cm-number">10</span>, <span class="cm-string">&quot;hello&quot;</span>]; <span class="cm-comment">// &#xC624;&#xB958;</span>
</code></pre>
<p>&#xC815;&#xD574;&#xC9C4; &#xC778;&#xB371;&#xC2A4;&#xC5D0; &#xC704;&#xCE58;&#xD55C; &#xC694;&#xC18C;&#xC5D0; &#xC811;&#xADFC;&#xD558;&#xBA74; &#xD574;&#xB2F9; &#xD0C0;&#xC785;&#xC774; &#xB098;&#xD0C0;&#xB0A9;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable">x</span>[<span class="cm-number">0</span>].<span class="cm-property">substring</span>(<span class="cm-number">1</span>)); <span class="cm-comment">// &#xC131;&#xACF5;</span>
<span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable">x</span>[<span class="cm-number">1</span>].<span class="cm-property">substring</span>(<span class="cm-number">1</span>)); <span class="cm-comment">// &#xC624;&#xB958;, &apos;number&apos;&#xC5D0;&#xB294; &apos;substring&apos; &#xC774; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.</span>
</code></pre>
<p>&#xC815;&#xD574;&#xC9C4; &#xC778;&#xB371;&#xC2A4; &#xC678;&#xC5D0; &#xB2E4;&#xB978; &#xC778;&#xB371;&#xC2A4;&#xC5D0; &#xC788;&#xB294; &#xC694;&#xC18C;&#xC5D0; &#xC811;&#xADFC;&#xD558;&#xBA74;, &#xC624;&#xB958;&#xAC00; &#xBC1C;&#xC0DD;&#xD558;&#xBA70; &#xC2E4;&#xD328;&#xD569;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-variable">x</span>[<span class="cm-number">3</span>] <span class="cm-operator">=</span> <span class="cm-string">&quot;world&quot;</span>; <span class="cm-comment">// &#xC624;&#xB958;, &apos;[string, number]&apos; &#xD0C0;&#xC785;&#xC5D0;&#xB294; &#xD504;&#xB85C;&#xD37C;&#xD2F0; &apos;3&apos;&#xC774; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.</span>

<span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable">x</span>[<span class="cm-number">5</span>].<span class="cm-property">toString</span>()); <span class="cm-comment">// &apos;[string, number]&apos; &#xD0C0;&#xC785;&#xC5D0;&#xB294; &#xD504;&#xB85C;&#xD37C;&#xD2F0; &apos;5&apos;&#xAC00; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.</span>
</code></pre>
<h1 id="&#xC5F4;&#xAC70;-enum">&#xC5F4;&#xAC70; (Enum)</h1>
<p>JavaScript&#xC758; &#xD45C;&#xC900; &#xC790;&#xB8CC;&#xD615; &#xC9D1;&#xD569;&#xACFC; &#xC0AC;&#xC6A9;&#xD558;&#xBA74; &#xB3C4;&#xC6C0;&#xC774; &#xB420;&#xB9CC;&#xD55C; &#xB370;&#xC774;&#xD130; &#xD615;&#xC740; <code>enum</code>&#xC785;&#xB2C8;&#xB2E4;.
C# &#xAC19;&#xC740; &#xC5B8;&#xC5B4;&#xCC98;&#xB7FC;, <code>enum</code>&#xC740; &#xAC12;&#xC758; &#xC9D1;&#xD569;&#xC5D0; &#xB354; &#xB098;&#xC740; &#xC774;&#xB984;&#xC744; &#xBD99;&#xC5EC;&#xC904; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-variable">enum</span> <span class="cm-variable">Color</span> {<span class="cm-variable">Red</span>, <span class="cm-variable">Green</span>, <span class="cm-variable">Blue</span>}
<span class="cm-keyword">let</span> <span class="cm-variable">c</span>: <span class="cm-variable-3">Color</span> <span class="cm-operator">=</span> <span class="cm-variable">Color</span>.<span class="cm-property">Green</span>;
</code></pre>
<p>&#xAE30;&#xBCF8;&#xC801;&#xC73C;&#xB85C;, <code>enum</code>&#xC740; <code>0</code>&#xBD80;&#xD130; &#xC2DC;&#xC791;&#xD558;&#xC5EC; &#xBA64;&#xBC84;&#xB4E4;&#xC758; &#xBC88;&#xD638;&#xB97C; &#xB9E4;&#xAE41;&#xB2C8;&#xB2E4;.
&#xBA64;&#xBC84; &#xC911; &#xD558;&#xB098;&#xC758; &#xAC12;&#xC744; &#xC218;&#xB3D9;&#xC73C;&#xB85C; &#xC124;&#xC815;&#xD558;&#xC5EC; &#xBC88;&#xD638;&#xB97C; &#xBC14;&#xAFC0; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC608;&#xB97C; &#xB4E4;&#xC5B4;, &#xC704; &#xC608;&#xC81C;&#xB97C; <code>0</code>&#xB300;&#xC2E0; <code>1</code>&#xBD80;&#xD130; &#xC2DC;&#xC791;&#xD574; &#xBC88;&#xD638;&#xB97C; &#xB9E4;&#xAE30;&#xB3C4;&#xB85D; &#xBC14;&#xAFC0; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-variable">enum</span> <span class="cm-variable">Color</span> {<span class="cm-variable">Red</span> <span class="cm-operator">=</span> <span class="cm-number">1</span>, <span class="cm-variable">Green</span>, <span class="cm-variable">Blue</span>}
<span class="cm-keyword">let</span> <span class="cm-variable">c</span>: <span class="cm-variable-3">Color</span> <span class="cm-operator">=</span> <span class="cm-variable">Color</span>.<span class="cm-property">Green</span>;
</code></pre>
<p>&#xB610;&#xB294;, &#xBAA8;&#xB4E0; &#xAC12;&#xC744; &#xC218;&#xB3D9;&#xC73C;&#xB85C; &#xC124;&#xC815;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-variable">enum</span> <span class="cm-variable">Color</span> {<span class="cm-variable">Red</span> <span class="cm-operator">=</span> <span class="cm-number">1</span>, <span class="cm-variable">Green</span> <span class="cm-operator">=</span> <span class="cm-number">2</span>, <span class="cm-variable">Blue</span> <span class="cm-operator">=</span> <span class="cm-number">4</span>}
<span class="cm-keyword">let</span> <span class="cm-variable">c</span>: <span class="cm-variable-3">Color</span> <span class="cm-operator">=</span> <span class="cm-variable">Color</span>.<span class="cm-property">Green</span>;
</code></pre>
<p><code>enum</code>&#xC758; &#xC720;&#xC6A9;&#xD55C; &#xAE30;&#xB2A5; &#xC911; &#xD558;&#xB098;&#xB294; &#xB9E4;&#xACA8;&#xC9C4; &#xAC12;&#xC744; &#xC0AC;&#xC6A9;&#xD574; enum &#xBA64;&#xBC84;&#xC758; &#xC774;&#xB984;&#xC744; &#xC54C;&#xC544;&#xB0BC; &#xC218; &#xC788;&#xB2E4;&#xB294; &#xAC83;&#xC785;&#xB2C8;&#xB2E4;.
&#xC608;&#xB97C; &#xB4E4;&#xC5B4;, &#xC704;&#xC758; &#xC608;&#xC81C;&#xC5D0;&#xC11C; <code>2</code>&#xB77C;&#xB294; &#xAC12;&#xC774; &#xC704;&#xC758; &#xC5B4;&#xB5A4; <code>Color</code> enum &#xBA64;&#xBC84;&#xC640; &#xB9E4;&#xCE6D;&#xB418;&#xB294;&#xC9C0; &#xC54C; &#xC218; &#xC5C6;&#xC744; &#xB54C;, &#xC774;&#xC5D0; &#xC77C;&#xCE58;&#xD558;&#xB294; &#xC774;&#xB984;&#xC744; &#xC54C;&#xC544;&#xB0BC; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-variable">enum</span> <span class="cm-variable">Color</span> {<span class="cm-variable">Red</span> <span class="cm-operator">=</span> <span class="cm-number">1</span>, <span class="cm-variable">Green</span>, <span class="cm-variable">Blue</span>}
<span class="cm-keyword">let</span> <span class="cm-variable">colorName</span>: <span class="cm-variable-3">string</span> <span class="cm-operator">=</span> <span class="cm-variable">Color</span>[<span class="cm-number">2</span>];

<span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-variable">colorName</span>); <span class="cm-comment">// &#xAC12;&#xC774; 2&#xC778; &apos;Green&apos;&#xC774; &#xCD9C;&#xB825;&#xB429;&#xB2C8;&#xB2E4;.</span>
</code></pre>
<h1 id="any">Any</h1>
<p>&#xC560;&#xD50C;&#xB9AC;&#xCF00;&#xC774;&#xC158;&#xC744; &#xB9CC;&#xB4E4; &#xB54C;, &#xC54C;&#xC9C0; &#xBABB;&#xD558;&#xB294; &#xD0C0;&#xC785;&#xC744; &#xD45C;&#xD604;&#xD574;&#xC57C; &#xD560; &#xC218;&#xB3C4; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774; &#xAC12;&#xB4E4;&#xC740; &#xC0AC;&#xC6A9;&#xC790;&#xB85C;&#xBD80;&#xD130; &#xBC1B;&#xC740; &#xB370;&#xC774;&#xD130;&#xB098; &#xC11C;&#xB4DC; &#xD30C;&#xD2F0; &#xB77C;&#xC774;&#xBE0C;&#xB7EC;&#xB9AC; &#xAC19;&#xC740; &#xB3D9;&#xC801;&#xC778; &#xCEE8;&#xD150;&#xCE20;&#xC5D0;&#xC11C; &#xC62C; &#xC218;&#xB3C4; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774; &#xACBD;&#xC6B0; &#xD0C0;&#xC785; &#xAC80;&#xC0AC;&#xB97C; &#xD558;&#xC9C0; &#xC54A;&#xACE0;, &#xADF8; &#xAC12;&#xB4E4;&#xC774; &#xCEF4;&#xD30C;&#xC77C; &#xC2DC;&#xAC04;&#xC5D0; &#xAC80;&#xC0AC;&#xB97C; &#xD1B5;&#xACFC;&#xD558;&#xAE38; &#xC6D0;&#xD569;&#xB2C8;&#xB2E4;.
&#xC774;&#xB97C; &#xC704;&#xD574;, <code>any</code> &#xD0C0;&#xC785;&#xC744; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">notSure</span>: <span class="cm-variable-3">any</span> <span class="cm-operator">=</span> <span class="cm-number">4</span>;
<span class="cm-variable">notSure</span> <span class="cm-operator">=</span> <span class="cm-string">&quot;maybe a string instead&quot;</span>;
<span class="cm-variable">notSure</span> <span class="cm-operator">=</span> <span class="cm-atom">false</span>; <span class="cm-comment">// &#xC131;&#xACF5;, &#xBD84;&#xBA85;&#xD788; &#xBD80;&#xC6B8;&#xC785;&#xB2C8;&#xB2E4;.</span>
</code></pre>
<p><code>any</code> &#xD0C0;&#xC785;&#xC740; &#xAE30;&#xC874;&#xC5D0; JavaScript&#xB85C; &#xC791;&#xC5C5;&#xD560; &#xC218; &#xC788;&#xB294; &#xAC15;&#xB825;&#xD55C; &#xBC29;&#xBC95;&#xC73C;&#xB85C;, &#xCEF4;&#xD30C;&#xC77C; &#xC911;&#xC5D0; &#xC810;&#xC9C4;&#xC801;&#xC73C;&#xB85C; &#xD0C0;&#xC785; &#xAC80;&#xC0AC;&#xB97C; &#xD558;&#xAC70;&#xB098; &#xD558;&#xC9C0; &#xC54A;&#xC744; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xD639; &#xB2E4;&#xB978; &#xC5B8;&#xC5B4;&#xC5D0;&#xC11C; &#xADF8;&#xB807;&#xB4EF;, <code>Object</code>&#xAC00; &#xBE44;&#xC2B7;&#xD55C; &#xC5ED;&#xD560;&#xC744; &#xD560; &#xC218; &#xC788;&#xC744; &#xAC83; &#xAC19;&#xB2E4;&#xACE0; &#xC0DD;&#xAC01;&#xD560; &#xC218;&#xB3C4; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xADF8;&#xB7F0;&#xB370;, <code>Object</code>&#xB85C; &#xC120;&#xC5B8;&#xB41C; &#xBCC0;&#xC218;&#xB4E4;&#xC740; &#xC624;&#xC9C1; &#xC5B4;&#xB5A4; &#xAC12;&#xC774;&#xB4E0; &#xADF8; &#xBCC0;&#xC218;&#xC5D0; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC788;&#xAC8C; &#xD574;&#xC8FC;&#xC9C0;&#xB9CC; &#xC2E4;&#xC81C;&#xB85C; &#xBA54;&#xC11C;&#xB4DC;&#xAC00; &#xC874;&#xC7AC;&#xD558;&#xB354;&#xB77C;&#xB3C4;, &#xC784;&#xC758;&#xB85C; &#xD638;&#xCD9C;&#xD560; &#xC218;&#xB294; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">notSure</span>: <span class="cm-variable-3">any</span> <span class="cm-operator">=</span> <span class="cm-number">4</span>;
<span class="cm-variable">notSure</span>.<span class="cm-property">ifItExists</span>(); <span class="cm-comment">// &#xC131;&#xACF5;, ifItExists &#xB294; &#xB7F0;&#xD0C0;&#xC784;&#xC5D4; &#xC874;&#xC7AC;&#xD560; &#xAC83;&#xC785;&#xB2C8;&#xB2E4;.</span>
<span class="cm-variable">notSure</span>.<span class="cm-property">toFixed</span>(); <span class="cm-comment">// &#xC131;&#xACF5;, toFixed&#xB294; &#xC874;&#xC7AC;&#xD569;&#xB2C8;&#xB2E4;. (&#xD558;&#xC9C0;&#xB9CC; &#xCEF4;&#xD30C;&#xC77C;&#xB7EC;&#xB294; &#xAC80;&#xC0AC;&#xD558;&#xC9C0; &#xC54A;&#xC74C;)</span>

<span class="cm-keyword">let</span> <span class="cm-variable">prettySure</span>: <span class="cm-variable-3">Object</span> <span class="cm-operator">=</span> <span class="cm-number">4</span>;
<span class="cm-variable">prettySure</span>.<span class="cm-property">toFixed</span>(); <span class="cm-comment">// &#xC624;&#xB958;: &#xD504;&#xB85C;&#xD37C;&#xD2F0; &apos;toFixed&apos;&#xB294; &apos;Object&apos;&#xC5D0; &#xC874;&#xC7AC;&#xD558;&#xC9C0; &#xC54A;&#xC2B5;&#xB2C8;&#xB2E4;.</span>
</code></pre>
<blockquote>
<p>Note: <a href="https://www.typescriptlang.org/docs/handbook/declaration-files/do-s-and-don-ts.html#general-types" target="_blank">Do&apos;s and Don&apos;ts</a>&#xC5D0; &#xC124;&#xBA85; &#xD588;&#xB4EF;&#xC774; <code>Object</code>&#xB97C; no-primitive <code>object</code> &#xB300;&#xC2E0;&#xC5D0; &#xC0AC;&#xC6A9;&#xD558;&#xC9C0; &#xB9C8;&#xC138;&#xC694;.</p>
</blockquote>
<p>&#xB610;&#xD55C;, any &#xD0C0;&#xC785;&#xC740; &#xD0C0;&#xC785;&#xC758; &#xC77C;&#xBD80;&#xB9CC; &#xC54C;&#xACE0; &#xC804;&#xCCB4;&#xB294; &#xC54C;&#xC9C0; &#xBABB;&#xD560; &#xB54C; &#xC720;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.
&#xC608;&#xB97C; &#xB4E4;&#xC5B4;, &#xC5EC;&#xB7EC; &#xB2E4;&#xB978; &#xD0C0;&#xC785;&#xC774; &#xC11E;&#xC778; &#xBC30;&#xC5F4;&#xC744; &#xB2E4;&#xB8F0; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">list</span>: <span class="cm-variable-3">any</span>[] <span class="cm-operator">=</span> [<span class="cm-number">1</span>, <span class="cm-atom">true</span>, <span class="cm-string">&quot;free&quot;</span>];

<span class="cm-variable">list</span>[<span class="cm-number">1</span>] <span class="cm-operator">=</span> <span class="cm-number">100</span>;
</code></pre>
<h1 id="void">Void</h1>
<p><code>void</code>&#xB294; &#xC5B4;&#xB5A4; &#xD0C0;&#xC785;&#xB3C4; &#xC874;&#xC7AC;&#xD560; &#xC218; &#xC5C6;&#xC74C;&#xC744; &#xB098;&#xD0C0;&#xB0B4;&#xAE30; &#xB54C;&#xBB38;&#xC5D0;, <code>any</code>&#xC758; &#xBC18;&#xB300; &#xD0C0;&#xC785; &#xAC19;&#xC2B5;&#xB2C8;&#xB2E4;.
<code>void</code>&#xB294; &#xBCF4;&#xD1B5; &#xD568;&#xC218;&#xC5D0;&#xC11C; &#xBC18;&#xD658; &#xAC12;&#xC774; &#xC5C6;&#xC744; &#xB54C; &#xBC18;&#xD658; &#xD0C0;&#xC785;&#xC744; &#xD45C;&#xD604;&#xD558;&#xAE30; &#xC704;&#xD574; &#xC4F0;&#xC774;&#xB294; &#xAC83;&#xC744; &#xBCFC; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">function</span> <span class="cm-variable">warnUser</span>(): <span class="cm-variable">void</span> {
    <span class="cm-variable">console</span>.<span class="cm-property">log</span>(<span class="cm-string">&quot;This is my warning message&quot;</span>);
}
</code></pre>
<p><code>void</code>&#xB97C; &#xD0C0;&#xC785; &#xBCC0;&#xC218;&#xB97C; &#xC120;&#xC5B8;&#xD558;&#xB294; &#xAC83;&#xC740; &#xC720;&#xC6A9;&#xD558;&#xC9C0; &#xC54A;&#xC740;&#xB370;, &#xC65C;&#xB0D0;&#xD558;&#xBA74; &#xADF8; &#xBCC0;&#xC218;&#xC5D0;&#xB294; <code>null</code>(<code>--strictNullChecks</code>&#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xC9C0; &#xC54A;&#xC744; &#xB54C;&#xB9CC; &#xD574;&#xB2F9;, &#xC790;&#xC138;&#xD55C; &#xAC74; &#xB2E4;&#xC74C; &#xC139;&#xC158;&#xC744; &#xCC38;&#xACE0;)&#xB610;&#xB294; <code>undefined</code> &#xB9CC; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC788;&#xAE30; &#xB54C;&#xBB38;&#xC785;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">unusable</span>: <span class="cm-variable-3">void</span> <span class="cm-operator">=</span> <span class="cm-atom">undefined</span>;
<span class="cm-variable">unusable</span> <span class="cm-operator">=</span> <span class="cm-atom">null</span>; <span class="cm-comment">// &#xC131;&#xACF5;  `--strictNullChecks` &#xC744; &#xC0AC;&#xC6A9;&#xD558;&#xC9C0; &#xC54A;&#xC744;&#xB54C;&#xB9CC;</span>
</code></pre>
<h1 id="null-and-undefined">Null and Undefined</h1>
<p>TypeScript&#xB294; <code>undefined</code> &#xACFC; <code>null</code> &#xB458; &#xB2E4; &#xAC01;&#xAC01; &#xC790;&#xC2E0;&#xC758; &#xD0C0;&#xC785; &#xC774;&#xB984;&#xC73C;&#xB85C; <code>undefined</code> , <code>null</code>&#xB85C; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.
<code>void</code>&#xCC98;&#xB7FC; &#xADF8; &#xC790;&#xCCB4;&#xB85C; &#xC720;&#xC6A9;&#xD55C; &#xACBD;&#xC6B0;&#xB294; &#xAC70;&#xC758; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-comment">// &#xC774; &#xBC16;&#xC5D0; &#xC774; &#xBCC0;&#xC218;&#xB4E4;&#xC5D0; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC788;&#xB294; &#xAC12;&#xC774; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;!</span>
<span class="cm-keyword">let</span> <span class="cm-variable">u</span>: <span class="cm-atom">undefined</span> <span class="cm-operator">=</span> <span class="cm-atom">undefined</span>;
<span class="cm-keyword">let</span> <span class="cm-variable">n</span>: <span class="cm-atom">null</span> <span class="cm-operator">=</span> <span class="cm-atom">null</span>;
</code></pre>
<p>&#xAE30;&#xBCF8;&#xC801;&#xC73C;&#xB85C; <code>null</code> &#xACFC; <code>undefined</code>&#xB294; &#xB2E4;&#xB978; &#xBAA8;&#xB4E0; &#xD0C0;&#xC785;&#xC758; &#xD558;&#xC704; &#xD0C0;&#xC785;&#xB2C8;&#xB2E4;.
&#xC774;&#xAC74;, null&#xACFC; undefined&#xB97C; <code>number</code> &#xAC19;&#xC740; &#xD0C0;&#xC785;&#xC5D0; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC788;&#xB2E4;&#xB294; &#xAC83;&#xC744; &#xC758;&#xBBF8;&#xD569;&#xB2C8;&#xB2E4;.</p>
<p>&#xD558;&#xC9C0;&#xB9CC;, <code>--strictNullChecks</code>&#xB97C; &#xC0AC;&#xC6A9;&#xD558;&#xBA74;, <code>null</code>&#xACFC;  <code>undefined</code>&#xB294; &#xC624;&#xC9C1; <code>any</code>&#xC640; &#xAC01;&#xC790; &#xC790;&#xC2E0;&#xB4E4; &#xD0C0;&#xC785;&#xC5D0;&#xB9CC; &#xD560;&#xB2F9; &#xAC00;&#xB2A5;&#xD569;&#xB2C8;&#xB2E4;. (&#xC608;&#xC678;&#xC801;&#xC73C;&#xB85C; <code>undefined</code>&#xB294; <code>void</code>&#xC5D0; &#xD560;&#xB2F9; &#xAC00;&#xB2A5;&#xD569;&#xB2C8;&#xB2E4;)
&#xC774;&#xAC74; &#xB9CE;&#xC740; &#xC77C;&#xBC18;&#xC801;&#xC778; &#xC5D0;&#xB7EC;&#xB97C; &#xBC29;&#xC9C0;&#xD558;&#xB294; &#xB370; &#xB3C4;&#xC6C0;&#xC744; &#xC90D;&#xB2C8;&#xB2E4;.
&#xC774; &#xACBD;&#xC6B0;, <code>string</code> &#xB610;&#xB294; <code>null</code> &#xB610;&#xB294; <code>undefined</code>&#xB97C; &#xD5C8;&#xC6A9;&#xD558;&#xACE0; &#xC2F6;&#xC740; &#xACBD;&#xC6B0; &#xC720;&#xB2C8;&#xC5B8; &#xD0C0;&#xC785;&#xC778; <code>string | null | undefined</code>&#xB97C; &#xC0AC;&#xC6A9;&#xD560; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<p>&#xC720;&#xB2C8;&#xC5B8; &#xD0C0;&#xC785;&#xC740; &#xC0C1;&#xAE09; &#xC8FC;&#xC81C;&#xB85C;, &#xC774;&#xD6C4; &#xCC55;&#xD130;&#xC5D0;&#xC11C; &#xB2E4;&#xB8F9;&#xB2C8;&#xB2E4;.</p>
<blockquote>
<p>As a note: &#xAC00;&#xB2A5;&#xD55C; &#xACBD;&#xC6B0; <code>--strictNullChecks</code>&#xB97C; &#xC0AC;&#xC6A9;&#xD560; &#xAC83;&#xC744; &#xAD8C;&#xC7A5;&#xD569;&#xB2C8;&#xB2E4;. &#xD558;&#xC9C0;&#xB9CC; &#xD578;&#xB4DC;&#xBD81;&#xC758; &#xBAA9;&#xC801;&#xC5D0; &#xB530;&#xB77C;, &#xC0AC;&#xC6A9;&#xD558;&#xC9C0; &#xC54A;&#xB294;&#xB2E4;&#xACE0; &#xAC00;&#xC815;&#xD569;&#xB2C8;&#xB2E4;.</p>
</blockquote>
<h1 id="never">Never</h1>
<p><code>never</code> &#xD0C0;&#xC785;&#xC740; &#xC808;&#xB300; &#xBC1C;&#xC0DD;&#xD560; &#xC218; &#xC5C6;&#xB294; &#xD0C0;&#xC785;&#xC744; &#xB098;&#xD0C0;&#xB0C5;&#xB2C8;&#xB2E4;.
&#xC608;&#xB97C; &#xB4E4;&#xC5B4;, <code>never</code>&#xB294; &#xD568;&#xC218; &#xD45C;&#xD604;&#xC2DD;&#xC774;&#xB098; &#xD654;&#xC0B4;&#xD45C; &#xD568;&#xC218; &#xD45C;&#xD604;&#xC2DD;&#xC5D0;&#xC11C; &#xD56D;&#xC0C1; &#xC624;&#xB958;&#xB97C; &#xBC1C;&#xC0DD;&#xC2DC;&#xD0A4;&#xAC70;&#xB098; &#xC808;&#xB300; &#xBC18;&#xD658;&#xD558;&#xC9C0; &#xC54A;&#xB294; &#xBC18;&#xD658; &#xD0C0;&#xC785;&#xC73C;&#xB85C; &#xC4F0;&#xC785;&#xB2C8;&#xB2E4;.
&#xBCC0;&#xC218; &#xB610;&#xD55C; &#xD0C0;&#xC785; &#xAC00;&#xB4DC;&#xC5D0; &#xC758;&#xD574; &#xC544;&#xBB34; &#xD0C0;&#xC785;&#xB3C4; &#xC5BB;&#xC9C0; &#xBABB;&#xD558;&#xAC8C; &#xC881;&#xD600;&#xC9C0;&#xBA74; <code>never</code> &#xD0C0;&#xC785;&#xC744; &#xC5BB;&#xAC8C; &#xB420; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<p><code>never</code>&#xD0C0;&#xC785;&#xC740; &#xBAA8;&#xB4E0; &#xD0C0;&#xC785;&#xC5D0; &#xD560;&#xB2F9; &#xAC00;&#xB2A5;&#xD55C; &#xD558;&#xC704; &#xD0C0;&#xC785;&#xC785;&#xB2C8;&#xB2E4;. &#xD558;&#xC9C0;&#xB9CC; &#xC5B4;&#xB5A4; &#xD0C0;&#xC785;&#xB3C4; <code>never</code>&#xC5D0; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC788;&#xAC70;&#xB098;, &#xD558;&#xC704; &#xD0C0;&#xC785;&#xC774; &#xC544;&#xB2D9;&#xB2C8;&#xB2E4;.(<code>never</code> &#xC790;&#xC2E0;&#xC740; &#xC81C;&#xC678;)
&#xC2EC;&#xC9C0;&#xC5B4; <code>any</code> &#xB3C4; <code>never</code>&#xC5D0; &#xD560;&#xB2F9;&#xD560; &#xC218; &#xC5C6;&#xC2B5;&#xB2C8;&#xB2E4;.</p>
<p><code>never</code>&#xB97C; &#xBC18;&#xD658;&#xD558;&#xB294; &#xBA87; &#xAC00;&#xC9C0; &#xC608;&#xC81C;&#xC785;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-comment">// never&#xB97C; &#xBC18;&#xD658;&#xD558;&#xB294; &#xD568;&#xC218;&#xB294; &#xD568;&#xC218;&#xC758; &#xB9C8;&#xC9C0;&#xB9C9;&#xC5D0; &#xB3C4;&#xB2EC;&#xD560; &#xC218; &#xC5C6;&#xB2E4;.</span>
<span class="cm-keyword">function</span> <span class="cm-variable">error</span>(<span class="cm-def">message</span>: <span class="cm-variable-3">string</span>): <span class="cm-variable">never</span> {
    <span class="cm-keyword">throw</span> <span class="cm-keyword">new</span> <span class="cm-variable">Error</span>(<span class="cm-variable">message</span>);
}

<span class="cm-comment">// &#xBC18;&#xD658; &#xD0C0;&#xC785;&#xC774; never&#xB85C; &#xCD94;&#xB860;&#xB41C;&#xB2E4;.</span>
<span class="cm-keyword">function</span> <span class="cm-variable">fail</span>() {
    <span class="cm-keyword">return</span> <span class="cm-variable">error</span>(<span class="cm-string">&quot;Something failed&quot;</span>);
}

<span class="cm-comment">// never&#xB97C; &#xBC18;&#xD658;&#xD558;&#xB294; &#xD568;&#xC218;&#xB294; &#xD568;&#xC218;&#xC758; &#xB9C8;&#xC9C0;&#xB9C9;&#xC5D0; &#xB3C4;&#xB2EC;&#xD560; &#xC218; &#xC5C6;&#xB2E4;.</span>
<span class="cm-keyword">function</span> <span class="cm-variable">infiniteLoop</span>(): <span class="cm-variable">never</span> {
    <span class="cm-keyword">while</span> (<span class="cm-atom">true</span>) {
    }
}
</code></pre>
<h1 id="&#xAC1D;&#xCCB4;-object">&#xAC1D;&#xCCB4; (Object)</h1>
<p><code>object</code>&#xB294; &#xC6D0;&#xC2DC; &#xD0C0;&#xC785;&#xC774; &#xC544;&#xB2CC; &#xD0C0;&#xC785;&#xC744; &#xB098;&#xD0C0;&#xB0C5;&#xB2C8;&#xB2E4;. &#xC608;&#xB97C; &#xB4E4;&#xC5B4;, <code>number</code>, <code>string</code>, <code>boolean</code>, <code>bigint</code>, <code>symbol</code>, <code>null</code>, &#xB610;&#xB294; <code>undefined</code> &#xAC00; &#xC544;&#xB2CC; &#xB098;&#xBA38;&#xC9C0;&#xB97C; &#xC758;&#xBBF8;&#xD569;&#xB2C8;&#xB2E4;.</p>
<p><code>object</code> &#xD0C0;&#xC785;&#xC744; &#xC4F0;&#xBA74;, <code>Object.create</code> &#xAC19;&#xC740; API &#xAC00; &#xB354; &#xC798; &#xB098;&#xD0C0;&#xB0A9;&#xB2C8;&#xB2E4;. &#xC608;&#xB97C; &#xB4E4;&#xC5B4;:</p>
<pre><code class="lang-ts"><span class="cm-variable">declare</span> <span class="cm-keyword">function</span> <span class="cm-variable">create</span>(<span class="cm-def">o</span>: <span class="cm-variable-3">object</span> <span class="cm-operator">|</span> <span class="cm-atom">null</span>): <span class="cm-variable">void</span>;

<span class="cm-variable">create</span>({ <span class="cm-property">prop</span>: <span class="cm-number">0</span> }); <span class="cm-comment">// &#xC131;&#xACF5;</span>
<span class="cm-variable">create</span>(<span class="cm-atom">null</span>); <span class="cm-comment">// &#xC131;&#xACF5;</span>

<span class="cm-variable">create</span>(<span class="cm-number">42</span>); <span class="cm-comment">// &#xC624;&#xB958;</span>
<span class="cm-variable">create</span>(<span class="cm-string">&quot;string&quot;</span>); <span class="cm-comment">// &#xC624;&#xB958;</span>
<span class="cm-variable">create</span>(<span class="cm-atom">false</span>); <span class="cm-comment">// &#xC624;&#xB958;</span>
<span class="cm-variable">create</span>(<span class="cm-atom">undefined</span>); <span class="cm-comment">// &#xC624;&#xB958;</span>
</code></pre>
<h1 id="&#xD0C0;&#xC785;-&#xB2E8;&#xC5B8;-type-assertions">&#xD0C0;&#xC785; &#xB2E8;&#xC5B8; (Type assertions)</h1>
<p>&#xAC00;&#xB054;, TypeScript&#xBCF4;&#xB2E4; &#xAC1C;&#xBC1C;&#xC790;&#xAC00; &#xAC12;&#xC5D0; &#xB300;&#xD574; &#xB354; &#xC798; &#xC54C;&#xACE0; &#xC77C;&#xC744; &#xB54C;&#xAC00; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xB300;&#xAC1C;, &#xC774;&#xB7F0; &#xACBD;&#xC6B0;&#xB294; &#xC5B4;&#xB5A4; &#xC5D4;&#xD2F0;&#xD2F0;&#xC758; &#xC2E4;&#xC81C; &#xD0C0;&#xC785;&#xC774; &#xD604;&#xC7AC; &#xD0C0;&#xC785;&#xBCF4;&#xB2E4; &#xB354; &#xAD6C;&#xCCB4;&#xC801;&#xC77C; &#xB54C; &#xBC1C;&#xC0DD;&#xD569;&#xB2C8;&#xB2E4;.</p>
<p><em>&#xD0C0;&#xC785; &#xB2E8;&#xC5B8;(Type assertions)</em> &#xC740; &#xCEF4;&#xD30C;&#xC77C;&#xB7EC;&#xC5D0;&#xAC8C; &quot;&#xB0A0; &#xBBFF;&#xC5B4;, &#xB09C; &#xB0B4;&#xAC00; &#xBB58; &#xD558;&#xACE0; &#xC788;&#xB294;&#xC9C0; &#xC54C;&#xC544;&quot;&#xB77C;&#xACE0; &#xB9D0;&#xD574;&#xC8FC;&#xB294; &#xBC29;&#xBC95;&#xC785;&#xB2C8;&#xB2E4;.
<code>&#xD0C0;&#xC785; &#xB2E8;&#xC5B8;</code>&#xC740; &#xB2E4;&#xB978; &#xC5B8;&#xC5B4;&#xC758; &#xD0C0;&#xC785; &#xBCC0;&#xD658;(&#xD615; &#xBCC0;&#xD658;)&#xACFC; &#xC720;&#xC0AC;&#xD558;&#xC9C0;&#xB9CC;, &#xB2E4;&#xB978; &#xD2B9;&#xBCC4;&#xD55C; &#xAC80;&#xC0AC;&#xB97C; &#xD558;&#xAC70;&#xB098; &#xB370;&#xC774;&#xD130;&#xB97C; &#xC7AC;&#xAD6C;&#xC131;&#xD558;&#xC9C0;&#xB294; &#xC54A;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xC774;&#xB294; &#xB7F0;&#xD0C0;&#xC784;&#xC5D0; &#xC601;&#xD5A5;&#xC744; &#xBBF8;&#xCE58;&#xC9C0; &#xC54A;&#xC73C;&#xBA70;, &#xC628;&#xC804;&#xD788; &#xCEF4;&#xD30C;&#xC77C;&#xB7EC;&#xB9CC; &#xC774;&#xB97C; &#xC0AC;&#xC6A9;&#xD569;&#xB2C8;&#xB2E4;.
&#xD0C0;&#xC785; &#xC2A4;&#xD06C;&#xB9BD;&#xD2B8;&#xB294; &#xAC1C;&#xBC1C;&#xC790;&#xAC00; &#xD544;&#xC694;&#xD55C; &#xC5B4;&#xB5A4; &#xD2B9;&#xC815; &#xAC80;&#xC0AC;&#xB97C; &#xC218;&#xD589;&#xD588;&#xB2E4;&#xACE0; &#xC778;&#xC9C0;&#xD569;&#xB2C8;&#xB2E4;.</p>
<p>&#xD0C0;&#xC785; &#xB2E8;&#xC5B8;&#xC5D0;&#xB294; &#xB450; &#xAC00;&#xC9C0; &#xD615;&#xD0DC;&#xAC00; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
&#xD558;&#xB098;&#xB294;, &quot;angle-bracket&quot; &#xBB38;&#xBC95;&#xC785;&#xB2C8;&#xB2E4;:</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">someValue</span>: <span class="cm-variable-3">any</span> <span class="cm-operator">=</span> <span class="cm-string">&quot;this is a string&quot;</span>;

<span class="cm-keyword">let</span> <span class="cm-variable">strLength</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> (<span class="cm-operator">&lt;</span><span class="cm-variable-3">string</span><span class="cm-operator">&gt;</span><span class="cm-variable">someValue</span>).<span class="cm-property">length</span>;
</code></pre>
<p>&#xB2E4;&#xB978; &#xD558;&#xB098;&#xB294; <code>as</code>-&#xBB38;&#xBC95; &#xC785;&#xB2C8;&#xB2E4;.</p>
<pre><code class="lang-ts"><span class="cm-keyword">let</span> <span class="cm-variable">someValue</span>: <span class="cm-variable-3">any</span> <span class="cm-operator">=</span> <span class="cm-string">&quot;this is a string&quot;</span>;

<span class="cm-keyword">let</span> <span class="cm-variable">strLength</span>: <span class="cm-variable-3">number</span> <span class="cm-operator">=</span> (<span class="cm-variable">someValue</span> <span class="cm-variable">as</span> <span class="cm-variable-3">string</span>).<span class="cm-property">length</span>;
</code></pre>
<p>&#xC704; &#xB450; &#xC608;&#xC81C;&#xB294; &#xB3D9;&#xC77C;&#xD569;&#xB2C8;&#xB2E4;.
&#xC5B4;&#xB5A4; &#xAC83;&#xC744; &#xC0AC;&#xC6A9;&#xD560;&#xC9C0;&#xB294; &#xC8FC;&#xB85C; &#xC120;&#xD638;&#xC5D0; &#xB530;&#xB978; &#xC120;&#xD0DD;&#xC785;&#xB2C8;&#xB2E4;. &#xD558;&#xC9C0;&#xB9CC; TypeScript&#xB97C; JSX&#xC640; &#xD568;&#xAED8; &#xC0AC;&#xC6A9;&#xD560; &#xB54C;&#xB294;, <code>as</code>-&#xC2A4;&#xD0C0;&#xC77C;&#xC758; &#xB2E8;&#xC5B8;&#xB9CC; &#xD5C8;&#xC6A9;&#xB429;&#xB2C8;&#xB2E4;.</p>
<h1 id="let&#xC5D0;-&#xAD00;&#xD558;&#xC5EC;"><code>let</code>&#xC5D0; &#xAD00;&#xD558;&#xC5EC;</h1>
<p>&#xC9C0;&#xAE08;&#xAE4C;&#xC9C0; &#xB354; &#xC775;&#xC219;&#xD560; &#xC218;&#xB3C4; &#xC788;&#xB294; JavaScript&#xC758; <code>var</code> &#xD0A4;&#xC6CC;&#xB4DC; &#xB300;&#xC2E0; <code>let</code> &#xD0A4;&#xC6CC;&#xB4DC;&#xB97C; &#xC774;&#xC6A9;&#xD588;&#xB2E4;&#xB294; &#xAC78; &#xC54C; &#xC218; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
<code>let</code> &#xD0A4;&#xC6CC;&#xB4DC;&#xB294; JavaScript ES2015&#xC5D0;&#xC11C; &#xC18C;&#xAC1C;&#xB418;&#xC5C8;&#xACE0;, <code>var</code>&#xBCF4;&#xB2E4; &#xC548;&#xC804;&#xD558;&#xB2E4;&#xB294; &#xC774;&#xC720;&#xB85C;, &#xD604;&#xC7AC; &#xD45C;&#xC900;&#xC73C;&#xB85C; &#xC5EC;&#xACA8;&#xC9C0;&#xACE0; &#xC788;&#xC2B5;&#xB2C8;&#xB2E4;.
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