Use GraphQL subscription to show progress of time-consuming operations

GraphQL is feature-rich query language designed to fit majority of needs of generic online applications. The 3 main types of operations in GraphQL are query, mutation and subscription. While queries and mutations are send in HTTP requests, subscriptions are running on WebSocket, which enables it to receive updates in real time. In this article, I would like to talk about using the subscription to report real-time results and/or progresses to time-consuming operations.

Measure per-letter dimension of text in JavaScript

TL;DR: Create a Range, set proper start and end points up to the text node with proper offset, then use Range.getBoundingClientRect() to get the dimensions.

As a part of the Lyricova Jukebox, we wanted to support inline karaoke swipe animation. With the time tags in the data, it is easy to figure out the time when the animation must reach a certain character. Then we need to figure out a way measure per character dimension for the animation to work.

How LyricsX keeps track of progress of media players

LyricsX is an open source software for macOS to download and display lyrics of current playing track on Music (previously iTunes), Spotify, Audirvana, Vox, Swinsian, or the Now Playing indicator in the OS. It gets time-tagged lyrics files from local storage or internet, and then display the lyrics in sync with the player.

As a crucial component of the development of Lyricova Jukebox, I have researched multiple implementations of real time lyrics display programs, and I found the mechanism behind LyricsX particularly interesting. Here in this article, I’d share with you how LyricsX tracking the player progress in a unique and resource-saving way.