javascript中，使用正则表达式实现'字符串截断翻页'

const TEMPLATE_NTH_OCCURANCE = '(?:(?:[^d]+d){n_1,}?)((?:[^d]+d){0,ps})';
// !!!使用之前，务必bind({pageSize: xxx<integer>, pageNo: xxx<integer>})!!!
function truncate(str, delimiterChar){
var pageSize = Math.max(+this.pageSize, 1), pageNo = Math.max(+this.pageNo, 1);
var regexp = new RegExp(TEMPLATE_NTH_OCCURANCE.replace(/d/g,   delimiterChar).
replace(/n_1/g, pageSize * (pageNo - 1)).
replace(/ps/g,  pageSize));
return (regexp.exec(str) || [])[1];
}

var func = truncate.bind({pageSize: 3, pageNo: 2});

func('1-a;2-b;3-d;4-d;5-e;', ';');//"4-d;5-e;"