ts-simple-ast
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TypeScript compiler wrapper for AST navigation and code generation.
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<h2 id="function-declarations">Function Declarations</h2>
<p>Functions can be retrieved from source files, other namespaces, or function bodies:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">functions</span> <span class="o">=</span> <span class="nx">sourceFile</span><span class="p">.</span><span class="nx">getFunctions</span><span class="p">();</span>
<span class="kd">const</span> <span class="nx">function1</span> <span class="o">=</span> <span class="nx">sourceFile</span><span class="p">.</span><span class="nx">getFunction</span><span class="p">(</span><span class="s2">"Function1"</span><span class="p">);</span>
<span class="kd">const</span> <span class="nx">firstFunctionWithChildFunction</span> <span class="o">=</span> <span class="nx">sourceFile</span><span class="p">.</span><span class="nx">getFunction</span><span class="p">(</span><span class="nx">f</span> <span class="o">=></span> <span class="nx">f</span><span class="p">.</span><span class="nx">getFunctions</span><span class="p">().</span><span class="nx">length</span> <span class="o">></span> <span class="mi">0</span><span class="p">);</span>
</code></pre>
</div>
<p>Most of the information you can get about functions is covered in other sections.</p>
<h3 id="addinsert">Add/Insert</h3>
<p>Add or insert enums to a source file, namespace, or function like declarations by calling <code class="highlighter-rouge">addFunction()</code>, <code class="highlighter-rouge">addFunctions()</code>, <code class="highlighter-rouge">insertFunction()</code>, or <code class="highlighter-rouge">insertFunctions()</code>.</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">functionDeclaration</span> <span class="o">=</span> <span class="nx">sourceFile</span><span class="p">.</span><span class="nx">addFunction</span><span class="p">({</span>
<span class="na">name</span><span class="p">:</span> <span class="s2">"FunctionName"</span>
<span class="p">});</span>
</code></pre>
</div>
<h3 id="remove">Remove</h3>
<p>Call <code class="highlighter-rouge">.remove()</code>:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">remove</span><span class="p">();</span>
</code></pre>
</div>
<h3 id="overloads">Overloads</h3>
<p>By default, in ambient contexts or for ambient nodes, all overloads will be returned. In non-ambient contexts, only the implementation will be returned.</p>
<p>Get the overloads by calling:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">overloads</span> <span class="o">=</span> <span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">getOverloads</span><span class="p">();</span> <span class="c1">// returns: FunctionDeclaration[]</span>
</code></pre>
</div>
<p>Or tell if the current declaration is an overload by calling either:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">isOverload</span><span class="p">();</span>
<span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">isImplementation</span><span class="p">();</span>
</code></pre>
</div>
<p>From the overloads, get the implementation by calling:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">implementation</span> <span class="o">=</span> <span class="nx">overload</span><span class="p">.</span><span class="nx">getImplementation</span><span class="p">();</span>
</code></pre>
</div>
<h4 id="addinsert-1">Add/Insert</h4>
<p>Add or insert overloads by using either the <code class="highlighter-rouge">.addOverload()</code>, <code class="highlighter-rouge">.addOverloads()</code>, <code class="highlighter-rouge">.insertOverload()</code>, or <code class="highlighter-rouge">insertOverloads()</code> methods.</p>
<h4 id="remove-1">Remove</h4>
<p>Call <code class="highlighter-rouge">.remove()</code> on the overload:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="nx">overload</span><span class="p">.</span><span class="nx">remove</span><span class="p">();</span>
</code></pre>
</div>
<h3 id="set-body-text">Set body text</h3>
<p>The body text can be set via the <code class="highlighter-rouge">.setBodyText()</code> method:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">setBodyText</span><span class="p">(</span><span class="s2">"const myNumber = 5;"</span><span class="p">);</span>
</code></pre>
</div>
<p>Or alternatively, write the body text with <a href="https://github.com/dsherret/code-block-writer">code-block-writer</a>:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="nx">functionDeclaration</span><span class="p">.</span><span class="nx">setBodyText</span><span class="p">(</span><span class="nx">writer</span> <span class="o">=></span> <span class="nx">writer</span><span class="p">.</span><span class="nx">writeLine</span><span class="p">(</span><span class="s2">"const myNumber = 5;"</span><span class="p">)</span>
<span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="s2">"if (myNumber === 5)"</span><span class="p">).</span><span class="nx">block</span><span class="p">(()</span> <span class="o">=></span> <span class="p">{</span>
<span class="nx">writer</span><span class="p">.</span><span class="nx">writeLine</span><span class="p">(</span><span class="s2">"console.log('yes')"</span><span class="p">);</span>
<span class="p">}));</span>
</code></pre>
</div>
<p>Using the writer is very useful because it will write code out using the indentation and newline settings of the AST. It’s also easier to use.</p>
<h3 id="unwrap">Unwrap</h3>
<p>A function declaration can be replaced with its body using the <code class="highlighter-rouge">.unwrap()</code> method.</p>
<p>Given the following code:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">function</span> <span class="nx">someFunction</span><span class="p">()</span> <span class="p">{</span>
<span class="kd">function</span> <span class="nx">innerFunction</span><span class="p">()</span> <span class="p">{</span>
<span class="p">}</span>
<span class="kd">const</span> <span class="nx">someDeclaration</span> <span class="o">=</span> <span class="mi">5</span><span class="p">;</span>
<span class="p">}</span>
</code></pre>
</div>
<p>Calling <code class="highlighter-rouge">.unwrap()</code> on the function will change the code to the following:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">function</span> <span class="nx">innerFunction</span><span class="p">()</span> <span class="p">{</span>
<span class="p">}</span>
<span class="kd">const</span> <span class="nx">someDeclaration</span> <span class="o">=</span> <span class="mi">5</span><span class="p">;</span>
</code></pre>
</div>
<h2 id="function-expressions">Function Expressions</h2>
<p>They exist in an expression:</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">add</span> <span class="o">=</span> <span class="kd">function</span><span class="p">(</span><span class="nx">a</span><span class="err">:</span> <span class="kr">number</span><span class="p">,</span> <span class="nx">b</span><span class="err">:</span> <span class="kr">number</span><span class="p">)</span> <span class="p">{</span> <span class="k">return</span> <span class="nx">a</span> <span class="o">+</span> <span class="nx">b</span><span class="p">;</span> <span class="p">};</span>
</code></pre>
</div>
<p>In this case, it can be retrieved via the variable declaration’s <a href="initializers">initializer</a>.</p>
<div class="language-typescript highlighter-rouge"><pre class="highlight"><code><span class="kd">const</span> <span class="nx">functionExpression</span> <span class="o">=</span> <span class="nx">sourceFile</span><span class="p">.</span><span class="nx">getVariableDeclarationOrThrow</span><span class="p">(</span><span class="s2">"add"</span><span class="p">).</span><span class="nx">getInitializerIfKindOrThrow</span><span class="p">(</span><span class="nx">ts</span><span class="p">.</span><span class="nx">SyntaxKind</span><span class="p">.</span><span class="nx">FunctionExpression</span><span class="p">);</span>
</code></pre>
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