sylarlong/iztro

iztro is a TypeScript library that generates astrology charts based on Zi Wei Dou Shu, an ancient Chinese astrology system sometimes called Purple Star Astrology. You provide a person's birth date (using either the Western solar calendar or the traditional Chinese lunar calendar), their birth time, and their gender, and the library calculates a full 12-palace birth chart along with details about the stars and fortune cycles associated with it. The library is published as an npm package and works in both Node.js projects and plain HTML pages via a CDN link. It supports multiple languages for both input and output, including Simplified Chinese, Traditional Chinese, English, Japanese, Korean, and Vietnamese. The README is written primarily in Chinese, but the library's documentation site has English content as well. What the library can compute includes: the placement of stars across the 12 palaces in the chart, major and minor fortune cycles, annual and monthly cycles, whether specific stars appear in a given palace or in the palaces that aspect it, and which transformations (a Zi Wei Dou Shu concept affecting a star's influence) are active at any given time. There is also a plugin and configuration system added in version 2.3.0 to accommodate the different schools of Zi Wei Dou Shu, which use slightly different rules for star brightness and transformations. The library handles the computational side of chart generation, such as calendar conversions and star placement rules. Developers can then focus on building the visual chart layout or the interpretive text on top of it. A companion online chart viewer at ziwei.pub shows what the output data looks like in a finished interface. The project is released under the MIT license.