How to use the oas-resolver.resolve function in oas-resolver

function main(str,source,options){
    let input = yaml.parse(str,{schema:'core'});
    resolver.resolve(input,source,options)
    .then(function(options){
        fs.writeFileSync(argv.output,yaml.stringify(options.openapi),'utf8');
    })
    .catch(function(err){
        console.warn(err);
    });
}

let obj = {};
    try {
        obj = JSON.parse(text);
    }
    catch (ex) {
        try {
            obj = yaml.parse(text);
            yamlMode = true;
        }
        catch (ex) {
            vscode.window.showErrorMessage('Could not parse OpenAPI document as JSON or YAML');
            console.warn(ex.message);
            return;
        }
    }
    resolver.resolve(obj, editor.document.fileName, {})
    .then(function(options){
        if (yamlMode) {
            vscode.workspace.openTextDocument({ language: 'yaml', content: yaml.stringify(options.openapi) })
            .then(function(doc) {
                vscode.window.showTextDocument(doc);
            })
            .then(function(ex) {
                console.error(ex);
            });
        }
        else {
            vscode.workspace.openTextDocument({ language: 'json', content: JSON.stringify(options.openapi, null, 2)})
            .then(function(doc) {
                vscode.window.showTextDocument(doc);
            })
            .then(function(ex){