Errors

Updated Nov 1, 2026

Textlane throws an Error whose code names what went wrong, so a caller can tell the cases apart without reading the message:

import { textlane } from "textlane"

let code = ""
try {
  textlane().use("md.nope")
} catch (error) {
  code = error.code
}
code
// unknown-plugin

Code	When
`unknown-plugin`	`use` names a plugin textlane does not have
`invalid-plugin`	`use` gets something that is neither a plugin, a list nor a preset
`invalid-options`	a plugin's options do not match its types, when the pipeline is built
`invalid-data`	`data(object)` gets something that is not an object
`frozen-processor`	`use` or a `data` setter is called on a frozen processor
`missing-parser`	`parse` or `process` runs with no parser in the pipeline
`missing-compiler`	`stringify` or `process` runs with no compiler in the pipeline
`invalid-stage`	a stage gets a tree it does not take, such as hast before `md.toHtml`
`async-in-sync`	`processSync` or `runSync` meets a stage with asynchronous work
`invalid-tree`	a tree given to `run` or `stringify` is not valid unist
`unsupported-node`	a tree given to `run` or `stringify` holds a node with no `type`
`unknown-node`	a compiler meets a node type it cannot write
`tree-too-deep`	a tree nests too deep to pass between Rust and JavaScript
`mdx-failed`	`mdx.compile` meets JavaScript it cannot compile
`unsafe-number`	`nl.indefiniteArticle` meets a number too large to read
`highlight-failed`	`html.highlight` cannot color a code block
`highlight-unavailable`	`html.highlight`'s grammars and themes failed to load

Syntax errors in MDX carry the upstream's source and rule as their code, as micromark-extension-mdx-expression:acorn for an expression that does not parse.

Options are checked when the pipeline is built, the first time it runs or freezes, not when use is called.