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JavaScript Callback Functions in JavaScript Introduction to Callback Functions Creating an Anonymous Callback Function

Leslio McKeown
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Leslio McKeown
Python Development Techdegree Student 9,441 Points
Posted by Leslio McKeown
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Leslio McKeown
Python Development Techdegree Student 9,441 Points

I don't understand what it is asking me

I don't know how to execute the app.js and I keep getting an error in the runner.js when I put

runner.js functionRunner(function() { console.log("Hello World!"); });

app.js 
function log() {

}
index.html 
<!DOCTYPE html>
<html lang="en">
    <head>
        <title></title>
        <link rel='stylesheet' href='styles.css'>
    </head>
    <body>
        <section>
            <p>Open your browser's console to see the results</p>
        </section>
        <script src='runner.js'></script>
        <script src='app.js'></script>
    </body>
</html>
runner.js 
functionRunner(function() {
  console.log("Hello World!");
});

1 Answer

Daniel Turato
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Daniel Turato
Java Web Development Techdegree Graduate 30,124 Points
Daniel Turato
.a{fill-rule:evenodd;}techdegree seal-36
Daniel Turato
Java Web Development Techdegree Graduate 30,124 Points

You have to do this:

functionRunner(() => {
    console.log("Hello World!");
});

This basically is an anonymous function with the () means no parameters and the body being a normal function. You use the arrow '=>' to create such a function.

You can read more about it here - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions