60 lines
1.8 KiB
HTML
60 lines
1.8 KiB
HTML
<link rel="stylesheet" href="style.css">
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<script type="module" src="codeblock.js"></script>
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<script type="module" src="scrollToTop.js"></script>
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<scroll-to-top>
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</scroll-to-top>
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<a class="back" href="..">Module Index</a>
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<h1 class="js module">debounce.js</h1>
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<code-block>import debounce from 'debounce.js'</code-block>
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<section>
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<h2>Description</h2>
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<p>
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Utility module for debouncing user-interactions (or any other events).
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</p>
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<p>
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Its main application are cases where expensive operations like updating or querying data are performed in response to some event like a user typing into a search box.
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</p>
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<dl>
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<code>
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<dt>debounce</dt>
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<dd>target ⟶ wrapper</dd>
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<dd>target, timeout ⟶ wrapper</dd>
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</code>
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<dd>
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A decorator function that takes a target function and returns a wrapper that will only call the target after a set timeout expires.
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Repeatedly calling the wrapper while the timeout is running will reset the timeout without calling the target function.
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</dd>
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</dl>
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<h2>Example</h2>
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<code-block>
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const update = value => expensive_operation(value)
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input.addEventListener("change", debounce(event => update(input.value)))
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</code-block>
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This code will debounce the update event handler of an input element, calling the <code>update</code>
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function only after no changes have been made for at least one second.
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<h2>Methods</h2>
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<p>
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The returned wrapper function has the following methods and properties:
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<dl>
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<dt><code>cancel()</code></dt>
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<dd>Cancels the running timeout without calling the target function.</dd>
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<dt><code>now(...)</code></dt>
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<dd>Cancels the running timeout and calls the target function immediately.</dd>
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<dt><code>running</code></dt>
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<dd><code>true</code> if there is a timeout currently running, <code>false</code> otherwise.</dd>
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</dl>
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</p>
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</section>
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