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

Understanding the 'json' parameter in the arrow function.

I am having a difficult time understanding the json parameter being used in the call-back arrow function (the one within the event handler). Why can't we just also call it data instead of json based on the sub-scope of the call-back arrow function? I've tried using data vs json for the parameter name, and the only difference I find is in the ordering of the astronauts list.

btn.addEventListener('click', () => { 
    getJSON(astrosUrl, (json) => { 
        json.people.map( person => {
            getJSON(wikiUrl + person.name, generateHTML);  

1 Answer


I think the name - data, json, item, x, el (for element) - is arbitrary, meaning it doesn't matter what you call it.

I think Guil just elected to call it json because that is the form the data is in and it's also appropriate since the function processing it is called getJSON.

I hope that helps.

Stay safe and happy coding!