function tex2svg( str, clbk ) {
		if ( !isString( str ) ) {
			throw new TypeError( format( 'invalid argument. First argument must be a string. Value: `%s`.', str ) );
		}
		if ( !isFunction( clbk ) ) {
			throw new TypeError( format( 'invalid argument. Callback argument must be a function. Value: `%s`.', clbk ) );
		}
		opts.math = str;
		mathjax.typeset( opts, done );
		/**
		* Callback invoked upon converting a string to SVG.
		*
		* @private
		* @param {Object} data - output
		* @returns {void}
		*/
		function done( data ) {
			var err;
			if ( data.errors ) {
				err = new Error( data.errors[ 0 ] );
				return clbk( err );
			}
			clbk( null, data.svg );
		}
	}
Converts a TeX or LaTeX string to an SVG.

@private
@param {string} str - string to convert
@param {Function} clbk - callback to invoke upon converting a string to an SVG
@throws {TypeError} first argument must be a string
@throws {TypeError} second argument must be a function
@returns {void}