seniority/yaml

YAML for configuration files, with no dependency (D-20260930-seniority-yaml).

parse(text) returns what js-yaml's load(text) returns — the value cosmiconfig hands its caller for a .yaml, a .yml or an extensionless rc file — for the part of YAML 1.2 that a configuration file is written in:

• block mappings and sequences, including a sequence at its key's own indentation and a mapping written inline after - ;
• flow […] and {…}, nested and across lines;
• plain scalars, one line or folded over several; single- and double-quoted scalars with every YAML escape; | and > block scalars with chomping and an indentation indicator;
• comments, --- / ... document markers, directives (skipped), anchors and aliases;
• the core schema js-yaml 5 loads by default: null, booleans, integers (0x, 0o), floats (.inf, .nan) and strings, and the !!str / !!int / … tags that force one.

Merge keys (<<) are an ordinary key here because they are in js-yaml 5's default load too: its CORE_SCHEMA leaves !!merge out. What this does not read is refused by name with the line and column — explicit ? keys and custom tags — never guessed at. A document is one document: a second --- with content is the same error load throws.

The errors are YAMLExceptions whose message is js-yaml's: the reason, then (line:column), 1-based. cosmiconfig prefixes YAML Error in <file>: and its own suite asserts the result, so the wording is the contract and is kept word for word where js-yaml has a word for it.

Nothing here imports anything, and no other module in the package imports this one (shape.test.ts holds both halves of that): a program that reads no YAML never loads it.

import { parse, YAMLException } from 'seniority/yaml';

FunctionsCopy Anchor Link

parseCopy Anchor Link

Read one YAML document into plain values. Throws YAMLException for anything outside the subset above, and for input that is not YAML at all.

function parse(text: string): unknown;

Returns unknown

ClassesCopy Anchor Link

YAMLExceptionCopy Anchor Link

A document this parser cannot read, with the reason and where.

class YAMLException extends Error {
    readonly reason: string;
    readonly mark: Mark | undefined;
    constructor(reason: string, mark?: Mark, snippet?: string);
}

InterfacesCopy Anchor Link

MarkCopy Anchor Link

Where an error is, 0-based, in the shape of js-yaml's mark.

interface Mark {
    line: number;
    column: number;
    position: number;
}