Dump adds quotes to some keys when using custom tag

[m-tartari]

As written in the title, yaml.dump adds quotes to some keys when using custom tags.

I've made a code sandbox (you can find here) and below a code sample where the issue is visible:

// sample.ts
import yaml from "js-yaml";

interface PoseType {
  x: number;
  y: number;
  z: number;
  rx: number;
  ry: number;
  rz: number;
  rw?: number;
}

class PoseTag {
  public pose: PoseType;
  constructor(props: PoseType) {
    this.pose = props;
  }
}

const PoseYamlType = new yaml.Type("!Pose", {
  kind: "mapping",
  resolve: (data) => {
    const val =
      typeof data.x === "number" &&
      typeof data.y === "number" &&
      typeof data.z === "number" &&
      typeof data.rx === "number" &&
      typeof data.ry === "number" &&
      typeof data.rz === "number" &&
      typeof data.rw === ("number" || "undefined");
    return val;
  },
  construct: (data: PoseType) => new PoseTag(data),
  instanceOf: PoseTag,
  represent: (obj: PoseTag) => obj.pose
});

// create schema
const schema = yaml.DEFAULT_SCHEMA.extend([PoseYamlType]);

const testPose: PoseType = {
  x: 2.46,
  y: 26.853,
  z: -9.792,
  rx: -0.969,
  ry: -0.001,
  rz: -0.233,
  rw: 0.078
};

const obj = new PoseTag(testPose);

const output = yaml.dump(obj, { schema: schema });
console.log(output);

expected output:

!Pose 
x: 2.46
y: 26.853
z: -9.792
rx: -0.969
ry: -0.001
rz: -0.233
rw: 0.078

received:

!Pose 
x: 2.46
'y': 26.853 # <---
z: -9.792
rx: -0.969
ry: -0.001
rz: -0.233
rw: 0.078

[rlidwka]

y without quotes is a boolean true value in YAML 1.0, old version of the spec: https://yaml.org/type/bool.html

so it's intentional, but we probably should drop support for that at some point

[rlidwka]

gonna close this, duplicate of #645

[rlidwka]

you can use

yaml.dump(obj, { schema: schema, noCompatMode: true });

it may be subject to change (maybe true by default) in next major version