Dump function not working with custom tag

First thanks for the great library!

I’m trying to build a YAML-JSON tool but got some trouble on the JSON->YAML part. Following the example, I build the custom type like below:

function ACustomTag(value) {
    this.klass = 'ACustomTag';
    this.value = value;
}
const customtagYamlType = new yaml.Type('!ACustomTag', {
    kind: 'scalar',
    resolve: data => !!data && typeof data === 'string' && data.trim(),
    construct: data => new ACustomTag(data),
    instanceOf: ACustomTag,
    represent: customTag => customTag.value
});

The JSON->YAML part works great, it translates my yaml file, which contains a !ACustomTag to the correct JSON object like

key: {
  klass: ACustomTag,
  value: 1
}

But when I try to use this result to serialize it back to YAML, this part is not recognized as a ACustomTag class instance. And the yaml result is like

key:
  klass: ACustomTag,
  value: 1

Instead of expection:

key: !AcustomTag 1

Is it some configuration part that I need to set to allow it converting custom tag back to YAML?

[GeekyDeaks]

Hi @hakimio - I noticed you are referring to load() and this issue is to do with the serialisation via dump() as the parsing is working - if your problem is actually related to load() can you start another issue and also include some code and YAML to show what you are doing and how you are using the schema? I’m not a maintainer btw, just a user of the module, but I’ll try and help if I can

[GeekyDeaks]

I tried your code snippet and it worked for me. Did you set the schema during the call to dump()?

https://github.com/nodeca/js-yaml/blob/665aadda42349dcae869f12040d9b10ef18d12da/lib/js-yaml/dumper.js#L810-L813

You can see the options here:

https://github.com/nodeca/js-yaml/blob/665aadda42349dcae869f12040d9b10ef18d12da/lib/js-yaml/dumper.js#L107-L118