YAML

YAML operators

Introduction

Custom operators for converting YAML

Usage

Configuration options

Option	Default	Description
indent?: number	2	Indentation width to use (in spaces) when serializing.
skipInvalid?: boolean	true	Do not throw on invalid types (like function in the safe schema) and skip pairs and single values with such types.
flowLevel?: number	-1	Specifies level of nesting, when to switch from block to flow style for collections. -1 means block style everwhere.
styles?: {[tag: string]: string}		"tag" => "style" map. Each tag may have own set of styles.
sortKeys?: boolean | ((a: any, b: any) => number);	false	If true, sort keys when dumping YAML. If a function, use the function to sort the keys.
lineWidth?: number	80	Set max line width for serialized output.
noRefs?: boolean	false	If true, don't convert duplicate objects into references.
noCompatMode?: boolean	false	If true don't try to be compatible with older yaml versions. Currently: don't quote "yes", "no" and so on, as required for YAML 1.1
condenseFlow?: boolean;	false	If true flow sequences will be condensed, omitting the space between a, b. Eg. '[a,b]', and omitting the space between key: value and quoting the key. Eg. '{"a":b}'. Can be useful when using yaml for pretty URL query params as spaces are %-encoded.

Nabu

When using the Nabu storage engine, the YAML plugin is included by default. If you want to pass configuration options you can do it like this

const store = Nabu
  .configure({
    yaml: { indent: 4 }
  })
  .bootstrap();

Memory storage engine

If you are using the memory storage engine the YAML plugin must be configured

import Memory from '@tashmet/memory';
import mingo from '@tashmet/mingo';
import yaml from '@tashmet/yaml';

const store = Memory
  .configure({})
  .use(mingo())
  .use(yaml({ /* configuration options */}))
  .bootstrap();

Operators

$yamlToObject

{ $yamlToObject: <expression> }

Convert a YAML string to an object

const data = dedent`
  title: foo
  list:
    - item1
    - item2
`;
const pipeline: Document[] = [
  { $documents: [{ data }] },
  { $set: { data: { $yamlToObject: '$data' } } }
];

const doc = await tashmet.db('test').aggregate(pipeline).next();

{ data: { title: 'foo', list: ['item1', 'item2'] } }

To convert YAML as front matter we need to specify some extra parameters

const data = dedent`
  ---
  title: foo
  ---
  Content goes here
`;
const pipeline: Document[] = [
  { $documents: [{ data }] },
  {
    $set: {
      data: {
        $yamlToObject: {
          data: '$data',
          frontMatter: true,
          contentKey: 'body'
        }
      } 
    }
  }
];
const doc = await tashmet.db('test').aggregate(pipeline).next();

{ data: { title: 'foo', body: 'Content goes here' } }

---

$objectToYaml

{ $objectToYaml: <expression> }

Convert an object to a YAML string

const input = [
  { data: { foo: 'bar' } }
];
const pipeline: Document[] = [
  { $documents: input },
  { $set: { data: { $objectToYaml: '$data' } } }
];

const doc = await tashmet.db('test').aggregate(pipeline).next();