How to use the yaml.Document function in yaml

parseAST (text: string) {
    const cst = YAML.parseCST(text)
    cst.setOrigRanges() // Workaround for CRLF eol, https://github.com/eemeli/yaml/issues/127
    const doc = new YAML.Document({ keepCstNodes: true }).parse(cst[0])

    const findPairs = (node: YAML.ast.AstNode | YAML.ast.Pair | null, path: string[] = []): KeyInDocument[] => {
      if (!node)
        return []
      if (node.type === 'MAP' || node.type === 'SEQ')
      // @ts-ignore
        return _.flatMap(node.items, m => findPairs(m, path))
      if (node.type === 'PAIR' && node.value != null && node.key != null) {
        if (!['BLOCK_FOLDED', 'BLOCK_LITERAL', 'PLAIN', 'QUOTE_DOUBLE', 'QUOTE_SINGLE'].includes(node.value.type)) {
          return findPairs(node.value, [...path, node.key.toString()])
        }
        else {
          const valueCST = node.value.cstNode
          if (!valueCST || !valueCST.valueRange)
            return []
          const { start, end, origStart, origEnd } = valueCST.valueRange

newConfig.wpInstall.users = [{
                'name': newConfig.wpInstall.adminUser,
                'email': newConfig.wpInstall.adminEmail,
                'password': newConfig.wpInstall.adminPassword,
                'role':'administrator'
              }]

              delete newConfig.wpInstall.adminUser
              delete newConfig.wpInstall.adminEmail
              delete newConfig.wpInstall.adminPassword
            }
          }

          try {

            const doc = new YAML.Document()
            doc.commentBefore = ' This is the new wordup config. All wordup specific config from package.json moved here.'
            doc.contents = newConfig

            fs.writeFileSync(this.getProjectPath('.wordup','config.yml'), doc.toString())

          } catch (err) {
            this.error(err, {exit:1})
          }

          this.log('INFO: The wordup config has been moved to .wordup/config.yml in your project folder.')
          this.log('')
      }
    }

  }

export function toYAML({ language, date, commit, items }: Translation) {
    const doc = new YAML.Document();
    doc.commentBefore = `
 Padloc Translation File

 language: ${language}
 date: ${date.toISOString()}
 commit: ${commit}
`;

    doc.contents = YAML.createNode(items.flatMap(item => [item.original, item.translation])) as any;

    for (const [i, item] of items.entries()) {
        const node = (doc.contents as any).items[i * 2];
        node.commentBefore = item.sources
            .map(
                ({ file, line, character, comment }) => ` ${file}:${line},${character}${comment ? ` (${comment})` : ""}`
            )