Method #isNumeric

www/js/ext/component.js:215–217

(c)

      return c >= "a" && c <= "z" || c >= "A" && c <= "Z";
    }
    #isNumeric(c) {
      return c >= "0" && c <= "9";
    }
    #isWhitespace(c) {
      return c === " " || c === "	" || c === "\r" || c === "\n";
    }