在zapier的代码中使用循环中的fetch

Question

I want to do 3 different api call from my zapier code, get their returns in variables and merge them. I can't figure out how to do that. It will be like:

var urls = [apiUrl1, apiUrl2, apiUrl3];
var output = [];

for ( i = 0; i < urls.length; i++ ) {
    output[i] = fetch( urls[i] );
}

This is an example code. I can't get response to output, it gets only a blank object {}. What will be the procedure to save the fetch return values in the output array?

Answer 1

Since apparently the folks at Zapier do not like to give out working examples or any sort of decent documentation for this level of code intricacy... here is a working example:

var promises = [];

for (var i = urls.length - 1; i >= 0; i--) {
    promises.push(fetch(urls[i]));
}

Promise.all(promises).then(function(res){
    var blobPromises = [];
    for (var i = res.length - 1; i >= 0; i--) {
        blobPromises.push(res[i].text());
    }
    return Promise.all(blobPromises);
}).then(function(body){
    var output = {id: 1234, rawData: body};
    callback(null, output);
}).catch(callback);

This may not be the cleanest solution, but it works for me. Cheers!

Answer 2

Two things you'll need to brush up on:

1. Promises - especially Promise.all() - there is lots out there about that.
2. Callback to return the data asynchronously. Our help docs describe this.

The main reason your code fails is because you are assuming the fetch happens immediately. In JavaScript that is not the case - it happens Async and you have to use promises and callbacks to wait until they are done before returning the output via the callback!