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JavaScript Asynchronous Programming with JavaScript Asynchronous JavaScript with Callbacks Implement a Callback

Hernan Diaz
Hernan Diaz
7,197 Points
Posted by Hernan Diaz
Hernan Diaz
7,197 Points

Why do we return callback return in getJSON(), this return is not used?

function getJSON(url, callback) { const xhr = new XMLHttpRequest(); xhr.open('GET', url); xhr.onload = () => { if(xhr.status === 200) { let data = JSON.parse(xhr.responseText); return callback(data); // <<<<<<<=========== HERE, we don't need it, do we? } }; xhr.send(); }

1 Answer

Farid Lavizadeh
Farid Lavizadeh
12,006 Points
Farid Lavizadeh
Farid Lavizadeh
12,006 Points

I believe it's used for the parameter (json). Then json.people.map uses the "data" as argument for json.