API Reference / API Methods / Promises, Callbacks & Errors
Apr. 17, 2019

Promises, Callbacks & Errors

Callbacks

Every API call takes a callback as the last parameter. This callback is then called with two arguments:

  • error: null or an Error object. More info on the error can be found in error.message.
  • content: the JavaScript object containing the response from the server.
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const algoliasearch = require('algoliasearch');
const client = algoliasearch('latency', '6be0576ff61c053d5f9a3225e2a90f76');
const index = client.initIndex('instant_search');

index.search({ query: 'query string' }, (err, { hits } = {}) => {
  if (err) {
    console.log(err);
    console.log(err.debugData);
    return;
  }

  console.log(hits);
});

Promises

If you don’t provide a callback, you get a promise (but never both).

We use jakearchibald/es6-promise as a polyfill when necessary.

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index.search({ query: 'query string' })
  .then(({ hits } = {}) => {
    console.log(hits);
  }).catch(err => {
    console.log(err);
    console.log(err.debugData);
  });

Async/Await

You can also use the async/await syntax to handle promises.

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(async () => {
  try {
    const content = await index.search({ query: 'query string' });
    console.log(content);
  } catch (err) {
    console.log(err);
    console.log(err.debugData);
  }
})();

Error Handling

The client sends errors when a method call fails. You can get detailed debugging information in err.debugData, which contains the array of requests parameters that were used to issue requests.

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