function checkOption(name, isStable, t) {
    var type, validNames;

    if (isStable) {
      type = "";
      validNames = options.validNames;
    } else {
      type = "unstable ";
      validNames = options.unstableNames;
    }

    name = name.trim();

    if (/^[+-]W\d{3}$/g.test(name)) {
      return true;
    }

    if (validNames.indexOf(name) === -1) {
      if (t.type !== "jslint" && !_.has(options.removed, name)) {
        error("E001", t, type, name);
        return false;
      }
    }

    return true;
  }
A lookup table for active directives whose keys are the value of the
directives and whose values are the tokens which enabled the directives.