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Callback functions on Javascript

function work(param, start, complete) {
    
    //i may be testing this wrong, but, at this point it works
    // start callback
    if (start != null) {
        console.log('starting the job\n');
        start();
    };

    console.log('\nim doing the work, please ' + param + ' wait in line \n');

    //end callback
    if (complete != null) {
        console.log('job done!\n');
        complete();
    };
}


// say it with love, say it with callbacks
//just call the main example function
work('User', function() {
        console.log('woow, im a start callback');
    },
    function() {
        console.log('im a complete callback');
    }
);

Description

a simple example on how to use basic callback functions on js, you can expand this example beyond that
https://snipt.net/embed/15426cfb17dab5871304857ef69b8f29/
/raw/15426cfb17dab5871304857ef69b8f29/
15426cfb17dab5871304857ef69b8f29
js
JavaScript
28
2019-07-19T04:01:27
True
False
False
Feb 20, 2014 at 04:32 AM
/api/public/snipt/115400/
callback-functions-on-javascript
<table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><a href="#L-1"> 1</a> <a href="#L-2"> 2</a> <a href="#L-3"> 3</a> <a href="#L-4"> 4</a> <a href="#L-5"> 5</a> <a href="#L-6"> 6</a> <a href="#L-7"> 7</a> <a href="#L-8"> 8</a> <a href="#L-9"> 9</a> <a href="#L-10">10</a> <a href="#L-11">11</a> <a href="#L-12">12</a> <a href="#L-13">13</a> <a href="#L-14">14</a> <a href="#L-15">15</a> <a href="#L-16">16</a> <a href="#L-17">17</a> <a href="#L-18">18</a> <a href="#L-19">19</a> <a href="#L-20">20</a> <a href="#L-21">21</a> <a href="#L-22">22</a> <a href="#L-23">23</a> <a href="#L-24">24</a> <a href="#L-25">25</a> <a href="#L-26">26</a> <a href="#L-27">27</a> <a href="#L-28">28</a></pre></div></td><td class="code"><div class="highlight"><pre><span></span><span id="L-1"><a name="L-1"></a><span class="kd">function</span> <span class="nx">work</span><span class="p">(</span><span class="nx">param</span><span class="p">,</span> <span class="nx">start</span><span class="p">,</span> <span class="nx">complete</span><span class="p">)</span> <span class="p">{</span> </span><span id="L-2"><a name="L-2"></a> </span><span id="L-3"><a name="L-3"></a> <span class="c1">//i may be testing this wrong, but, at this point it works</span> </span><span id="L-4"><a name="L-4"></a> <span class="c1">// start callback</span> </span><span id="L-5"><a name="L-5"></a> <span class="k">if</span> <span class="p">(</span><span class="nx">start</span> <span class="o">!=</span> <span class="kc">null</span><span class="p">)</span> <span class="p">{</span> </span><span id="L-6"><a name="L-6"></a> <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s1">&#39;starting the job\n&#39;</span><span class="p">);</span> </span><span id="L-7"><a name="L-7"></a> <span class="nx">start</span><span class="p">();</span> </span><span id="L-8"><a name="L-8"></a> <span class="p">};</span> </span><span id="L-9"><a name="L-9"></a> </span><span id="L-10"><a name="L-10"></a> <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s1">&#39;\nim doing the work, please &#39;</span> <span class="o">+</span> <span class="nx">param</span> <span class="o">+</span> <span class="s1">&#39; wait in line \n&#39;</span><span class="p">);</span> </span><span id="L-11"><a name="L-11"></a> </span><span id="L-12"><a name="L-12"></a> <span class="c1">//end callback</span> </span><span id="L-13"><a name="L-13"></a> <span class="k">if</span> <span class="p">(</span><span class="nx">complete</span> <span class="o">!=</span> <span class="kc">null</span><span class="p">)</span> <span class="p">{</span> </span><span id="L-14"><a name="L-14"></a> <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s1">&#39;job done!\n&#39;</span><span class="p">);</span> </span><span id="L-15"><a name="L-15"></a> <span class="nx">complete</span><span class="p">();</span> </span><span id="L-16"><a name="L-16"></a> <span class="p">};</span> </span><span id="L-17"><a name="L-17"></a><span class="p">}</span> </span><span id="L-18"><a name="L-18"></a> </span><span id="L-19"><a name="L-19"></a> </span><span id="L-20"><a name="L-20"></a><span class="c1">// say it with love, say it with callbacks</span> </span><span id="L-21"><a name="L-21"></a><span class="c1">//just call the main example function</span> </span><span id="L-22"><a name="L-22"></a><span class="nx">work</span><span class="p">(</span><span class="s1">&#39;User&#39;</span><span class="p">,</span> <span class="kd">function</span><span class="p">()</span> <span class="p">{</span> </span><span id="L-23"><a name="L-23"></a> <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s1">&#39;woow, im a start callback&#39;</span><span class="p">);</span> </span><span id="L-24"><a name="L-24"></a> <span class="p">},</span> </span><span id="L-25"><a name="L-25"></a> <span class="kd">function</span><span class="p">()</span> <span class="p">{</span> </span><span id="L-26"><a name="L-26"></a> <span class="nx">console</span><span class="p">.</span><span class="nx">log</span><span class="p">(</span><span class="s1">&#39;im a complete callback&#39;</span><span class="p">);</span> </span><span id="L-27"><a name="L-27"></a> <span class="p">}</span> </span><span id="L-28"><a name="L-28"></a><span class="p">);</span> </span></pre></div> </td></tr></table>
callbacks, javascript, js