Photo By Zhi Sun (Reflection Lake, Mt.Rainier)

In front-end engineering interviews and daily front-end development, we encounter Promises all the time. In these interviews, I have been asked to implement a Promise from scratch, implement Promise.all(), write a function to limit maximum concurrent Promises and multiple questions about code sequencing around Promises. In daily front-end development, we use Promises to fetch data and ensure our code runs in the correct sequence.

When asked about Promises in interviews I always get a little afraid. I know how to use Promises and some basic rules but if things get fancy I fear I will fail. I searched online and…

Zhi Sun

Software Engineer

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