Function next

docs/assets/js/add-preview-buttons.js:50654–50673

(c)

	        throw error;
	    },
	        next = function next(c) {

	        // If a c parameter is provided, verify that it matches the current character.

	        if (c && c !== ch) {
	            error("Expected " + renderChar(c) + " instead of " + renderChar(ch));
	        }

	        // Get the next character. When there are no more characters,
	        // return the empty string.

	        ch = text.charAt(at);
	        at++;
	        columnNumber++;
	        if (ch === '\n' || ch === '\r' && peek() !== '\n') {
	            lineNumber++;
	            columnNumber = 0;
	        }
	        return ch;
	    },
	        peek = function peek() {

	        // Get the next character without consuming it or