@sap/cds-dk/bin/data-products/merge-csns.js

Command line client and development toolkit for the SAP Cloud Application Programming Model

'use strict'

/**
 * Merges multiple partial CSNs (Core Schema Notations) into a single CSN.
 * @param {Array<object>} partialCsns - An array of partial CSN objects to be merged.
 * @returns {object} - The merged CSN object.
 * @throws Will throw an error if there are conflicting definitions or translations.
 */
exports.mergePartialCsns = function (partialCsns) {
  const parentCsn = { definitions: Object.create(null), i18n: Object.create(null) }

  for (const partialCsn of partialCsns) {
    for (const definitionName in partialCsn.definitions) {
      const definition = partialCsn.definitions[definitionName]
      if (parentCsn.definitions[definitionName]) {
        const existing = JSON.stringify(parentCsn.definitions[definitionName])
        const current = JSON.stringify(definition)
        if (existing !== current) {
          throw new Error('Error for definition ' + definitionName + ' - it already exists!')
        }
      } else {
        parentCsn.definitions[definitionName] = definition
      }
    }

    for (const i18nLanguageCode in partialCsn.i18n) {
      const i18n = partialCsn.i18n[i18nLanguageCode]
      if (!parentCsn.i18n[i18nLanguageCode]) {
        parentCsn.i18n[i18nLanguageCode] = Object.create(null)
      }

      for (const translationCode in i18n) {
        if (parentCsn.i18n[i18nLanguageCode][translationCode]) {
          const existing = parentCsn.i18n[i18nLanguageCode][translationCode]
          const current = i18n[translationCode]
          if (existing !== current) {
            throw new Error('Error for i18n:' + i18nLanguageCode + ' with translation ' + translationCode + ' - it already exists!')
          }
        }
        parentCsn.i18n[i18nLanguageCode][translationCode] = i18n[translationCode]
      }
    }
  }

  return parentCsn
}