* Return an options object with a cramped version of the current style. If * the current style is cramped, returns `this`.

* Parses an entire function, including its base and all of its arguments.

* If `optional` is false or absent, this parses an ordinary group, * which is either a single nucleus (like "x") or an expression * in braces (l

* Parses a group, essentially returning the string formed by the * brace-enclosed tokens plus some position information.

* Get the style of a subscript given a base in the current style.

* Get the style of a superscript given a base in the current style.

* Create a cached version of a pure function.

* Create a cached version of a pure function.

* Create a cached version of a pure function.

处理http响应成败

* Support testing using an element * @param {Function} fn Passed the created div and expects a boolean result

* Support testing using an element * @param {Function} fn Passed the created div and expects a boolean result