What causes "missing built-in keyword ${name}" in can1357/oh-my-pi?

Use an exact built-in keyword name (check the library's keyword table/docs)

can1357/oh-my-pi · error · OmpTypeError

missing built-in keyword ${name}

Error message

missing built-in keyword ${name}

What it means

keywordSchema() looks up a built-in keyword's IR via keywordIR(name); if the keyword is not registered, it throws OmpTypeError. Only names present in the built-in keyword table (string, number, boolean, etc.) are valid; anything else must go through parseDef or a user-defined alias.

Source

Thrown at packages/omptype/src/type.ts:2794

	readonly numeric: ParsedStringKeyword<number>;
	readonly regex: FluentType<string>;
	readonly semver: FluentType<string>;
	readonly trim: PreformattedKeyword;
	readonly upper: PreformattedKeyword;
	readonly url: ParsedStringKeyword<URL>;
	readonly uuid: UuidKeyword;
}

/** Number keyword module attached to `type.number`. */
export interface NumberKeyword extends FluentType<number> {
	readonly integer: FluentType<number>;
}

type Constructed<ctor> = ctor extends abstract new (...args: never[]) => infer instance ? instance : never;

function keywordSchema<output = string, input = output>(name: string): FluentType<output, input> {
	const ir = keywordIR(name);
	if (ir === undefined) throw new OmpTypeError(`missing built-in keyword ${name}`);
	return makeType<output, input>(ir, [], {});
}

function parsedKeyword<parsed>(name: string): ParsedStringKeyword<parsed> {
	return Object.assign(keywordSchema<string>(name), {
		parse: keywordSchema<parsed, string>(`${name}.parse`),
	});
}

function preformattedKeyword(name: string): PreformattedKeyword {
	return Object.assign(keywordSchema<string, string>(name), {
		preformatted: keywordSchema(`${name}.preformatted`),
	});
}

type MatchDefault<input = unknown, output = unknown> =
	| "assert"
	| "never"

View on GitHub (pinned to 9690622007)

Solutions

Use an exact built-in keyword name (check the library's keyword table/docs)
Fix typos in the keyword string
For custom names, register an alias with the type registry instead of calling keywordSchema directly
If upgrading, check the changelog for renamed/removed keywords and update call sites

Example fix

// before
const s = keywordSchema('strn'); // throws
// after
const s = keywordSchema('string');

Defensive patterns

Strategy: fallback

Validate before calling

import { type } from '@oh-my-pi/omptype';
function safeKeyword(name: string) {
  try {
    const t = type(name);
    return t;
  } catch {
    return null; // not a built-in keyword
  }
}

Try / catch

try {
  const s = keywordSchema(name);
} catch (err) {
  if (err instanceof OmpTypeError && err.message.startsWith('missing built-in keyword')) {
    return type(name); // route unknown names through the parser / alias registry
  }
  throw err;
}

Prevention

Keep a checked list of valid keyword names and validate against it
Never build keyword names by string concatenation without verification
On upgrades, diff your keyword usage against the library's keyword table

When it happens

Trigger: Calling keywordSchema()/parsedKeyword()/fluent keyword helpers with a name that isn't a built-in, e.g. keywordSchema('strn'), or a keyword removed/renamed in a newer library version.

Common situations: Typo'd keyword names; building keyword names dynamically from config/data; version upgrades where a keyword was renamed or an unregistered custom keyword was assumed to be built-in.

Related errors

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/096f8cb07ea23817. Report an issue: GitHub.