js-yaml sourcemaps

A library for finding YAML source locations after parsing by js-yaml.

Installation

npm install js-yaml-source-map js-yaml

Usage

1---
2# file: example.yaml
3fruits:
4  - apple
5  - banana
6  - orange
7people:
8  - name: Eric
9    age: 26
10  - name: Lily
11    age: 22
12states:
13  CA: California
14  NY: New York
15    capital: Albany
16  TX: Texas

1import fs from "fs";
2import yaml from "js-yaml";
3import SourceMap from "js-yaml-source-map";
4
5const data = fs.readFileSync("./example.yaml", "utf8");
6
7const map = new SourceMap();
8// pass map.listen() to the listener option
9const loaded = yaml.load(data, { listener: map.listen() });
10
11console.log(loaded); // { fruits: [ 'apple', 'banana', 'orange' ], ... }
12
13// different syntaxes supported
14console.log(map.lookup("fruits")); // { line: 4, column: 10, position: 42 }
15console.log(map.lookup("people.0.age")); // { line: 9, column: 8, position: 95 }
16console.log(map.lookup(".people[1].name")); // { line: 10, column: 9, position: 108}
17console.log(map.lookup(["states", "NY", "capital"])); // { line: 16, column: 12, position: 188 }

If you're using CommonJS, you'll need to access the default key:

1const SourceMap = require("js-yaml-source-map").default;
2
3const map = new SourceMap();
4
5//...

API Reference

SourceMap

Constructor: new SourceMap()

Properties:

• SourceMap().map: PathMap

Methods:

• SourceMap().listen(): (event: "open" | "close", state: State) => void
• SourceMap().lookup(path: string | string[]): SourceLocation | undefined

Types

1interface PathMap {
2  [path: string]: {
3    line: number;
4    position: number;
5    lineStart: number;
6  };
7}
8
9interface SourceLocation {
10  line: number;
11  column: number;
12  position: number;
13}

Limitations

• This library does not work with multi-document sources and yaml.loadAll(). Using it with yaml.loadAll() will result in undefined behavior.
• Using arrays or objects as keys will not work properly, and will result in undefined behavior.