removePattern(pattern) {
    const pkg = this.patterns[pattern];
    if (!pkg) {
      return;
    }

    const byName = this.patternsByPackage[pkg.name];
    if (!byName) {
      return;
    }

    byName.splice(byName.indexOf(pattern), 1);
    delete this.patterns[pattern];
  }
Parse input strings like `package-1/package-2` to an array of packages