makestatic-verify-id/index.js

Verify id attributes are unique

/**
 *  Verify `id` attributes in HTML documents are unique.
 *
 *  @class VerifyId
 *
 *  @see /docs/api/graph-resources/
 */
class VerifyId {

  /**
   *  Verifies that `id` attributes are unique in each HTML document.
   *
   *  When `strict` is disabled an error is not thrown but a warning message is
   *  logged.
   *
   *  @function after
   *  @member VerifyId
   *
   *  @param {Object} context the processing context.
   *  @param {Object} options the plugin options.
   *
   *  @option {Boolean=true} [strict] warn rather than error when `false`.
   *
   *  @throws Error if no resource graph is available.
   *  @throws Error when a duplicate id attribute is detected in `strict` mode.
   */
  after (context, options = {}) {
    const log = context.log
    const strict = options.strict === undefined ? true : options.strict
    if (!context.graph) {
      throw new Error(`verify-id expects a resource graph, use graph-resources`)
    }

    function error (err) {
      if (!strict) {
        return log.warn(err.message)
      }
      throw err
    }

    context.graph.htmlDocuments.forEach((doc) => {
      const identifiers = doc.identifiers
      let k
      let v
      for (k in identifiers) {
        v = identifiers[k]
        if (v.length > 1) {
          error(new Error(`duplicate id attribute '${k}' in ${doc.file.path}`))
        }
      }
    })
  }
}

module.exports = VerifyId