Inconsistent quotes presence in yaml

Prettier 1.14.3 Playground link

--parser yaml

Input:

key1: value1
key2: 'value2'

Output:

key1: value1
key2: "value2"

Expected behavior:

Consistent quoting. Personally,

I would prefer to see optional quotes removed. This matches how prettier handles JavaScript object keys.

key1: value1
key2: value2

Enforcing quotes would also be acceptable. The most important thing is consistency.

[tuukka]

Could this be implemented at least for simple string keys for now?

Prettier 2.0.5 Playground link

--parser yaml

Input:

key1: value1
"key2": value2

Output:

key1: value1
"key2": value2

Expected behavior:

key1: value1
key2: value2

[remcohaszing]

YAML seems so simple, but it turns out it isn’t.

At this moment, Prettier seems to support the failsafe schema. This means it supports mappings, sequences, and uninterpreted strings.

This the following YAML

foo: 1

is equivalent to the following JSON

{"foo": "1"}

When the JSON schema is used, it would be equivalent to the following JSON

{"foo": 1}

The core schema adds even more notations.

And then there are custom schemas, so detecting wether it is safe to unquote strings is never safe. For example, http://yaml.org/type/ adds support for time stamps and yes / no as boolean values (which is default in YAML 1.1).

Prettier could add support for stricter YAML formatting, if it gets an option for the user to support a schema. This could even go beyond normalization of strings, such as stripping tags and normalizing type casing.