import {values} from 'micromark-util-symbol/values.js'

/**
 * Normalize an identifier (such as used in definitions).
 *
 * @param {string} value
 * @returns {string}
 */
export function normalizeIdentifier(value) {
  return (
    value
      // Collapse Markdown whitespace.
      .replace(/[\t\n\r ]+/g, values.space)
      // Trim.
      .replace(/^ | $/g, '')
      // Some characters are considered “uppercase”, but if their lowercase
      // counterpart is uppercased will result in a different uppercase
      // character.
      // Hence, to get that form, we perform both lower- and uppercase.
      // Upper case makes sure keys will not interact with default prototypal
      // methods: no method is uppercase.
      .toLowerCase()
      .toUpperCase()
  )
}