cryptpad/www/common/text-cursor.js

define([
], function () {
    var module = { exports: {} };
    var transformCursor = function (cursor, op) {
        if (!op) { return cursor; }

        var pos = op.offset;
        var remove = op.toRemove;
        var insert = op.toInsert.length;
        if (typeof cursor === 'undefined') { return; }
        if (typeof remove === 'number' && pos < cursor) {
            cursor -= Math.min(remove, cursor - pos);
        }
        if (typeof insert === 'number' && pos < cursor) {
            cursor += insert;
        }
        return cursor;
    };
    module.exports.transformCursor = function (cursor, ops) {
        if (Array.isArray(ops)) {
            for (var i = ops.length - 1; i >= 0; i--) {
                cursor = transformCursor(cursor, ops[i]);
            }
            return cursor;
        }
        return transformCursor(ops);
    };
    return module.exports;
});