@mapwhit/style-expressions/lib/expression/types/collator.js

Process expressions in map style.

export class Collator {
  constructor(caseSensitive, diacriticSensitive, locale) {
    if (caseSensitive) this.sensitivity = diacriticSensitive ? 'variant' : 'case';
    else this.sensitivity = diacriticSensitive ? 'accent' : 'base';

    this.locale = locale;
    this.collator = new Intl.Collator(this.locale ? this.locale : [], {
      sensitivity: this.sensitivity,
      usage: 'search'
    });
  }

  compare(lhs, rhs) {
    return this.collator.compare(lhs, rhs);
  }

  resolvedLocale() {
    // We create a Collator without "usage: search" because we don't want
    // the search options encoded in our result (e.g. "en-u-co-search")
    return new Intl.Collator(this.locale ? this.locale : []).resolvedOptions().locale;
  }
}