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AnsiML - Markup Language for ANSI Colors

AnsiML is a library for inserting ANSI Colors into strings, implemented in TypeScript for Deno. Text and colors are strictly separated, thus enabling semantic operations on ANSI colored text and rendering to different output formats.

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Introduction

ANSI colors are character codes for adding colors to console output. Yet, once the color codes are mixed with the text, operations on the text become difficult. Consider these scenarios:

  • We want to print colored text with a maximum of 80 columns. If we do not handle the color codes while calculating the positions of the line breaks, the lines will end up shorter than they need to be.

  • We want to print syntax-highlighted source code with colored line numbers to the console. Inserting the line numbers into the source might break the parser of the syntax highlighter. Inserting the line numbers after syntax highlighting might overwrite the colors of the highlighted code.

AnsiML solves this with an intermediate representation that keeps color codes separate from the actual text. It represents colored text as a tree of terminal string values and non-terminal node objects. Each node object can have a sequence of color commands, allowing for hierarchical styling of the text. See the examples folder for more.

Features

  • Rendering to ANSI colored text, HTML, or plain text.
  • JSX runtime for using JSX syntax to create AnsiML trees.
  • Generic stringify function for custom commands and output formats.
  • High-level Styled component for nicer dev experience.

Note on jsx-runtime

The modern way of configuring JSX is via the jsxImportSource compiler option, specified either in the compilerOptions section or as a pragma comment. This can be an URL or bare specifier (defined in an import map). TypeScript will then append /jsx-runtime to this specifier and try to import it as a module. This module is expected to export the JSX related functions, such as jsx, jsxs, and Fragment.

Unfortunately, Deno will fail to interpret a module named jsx-runtime as a TypeScript module because it does not end in .ts or .tsx. The workaround is to host the module on a CDN that serves the module with the correct MIME type. In order to run the examples in the repository locally, use deno run -A server.ts.Ø