js写的string.format函数

String.prototype.format2 = function (args) { var s = this, vals = [], rst = [], pattern = /({|})/g, ms = s.match(pattern); var err = ['输入字符串的格式不正确。', '索引(从零开始)必须大于或等于零，且小于参数列表的大小。', '值不能为null。', '格式说明符无效。']; if (ms.length % 2 != 0) { throw new Error(err[0]); } var matchs = s.match(/({+[-\d]+(:[\D\d]*?)*?}+)|({+([\D]*?|[:\d]*?)}+)|({{[\w]*?)|([\w]*?}})/g); if (matchs != null) { if (arguments.length > 1) { for (var i = 0, c = arguments.length; i < c; i++) { if (arguments[i] != undefined) { vals.push(arguments[i]); } } } else if (Object.prototype.toString.call(args) === '[object Array]') { vals = args; } else if (args != undefined && args != null) { vals.push(args); } var len = vals.length; for (var i = 0, c = matchs.length; i < c; i++) { var _t = matchs[i], _tv = _t.replace(pattern, ''), _p = s.indexOf(_t), idx = parseInt(_tv, 10); var _c = /{/g.test(_t) ? _t.match(/{/g).length : 0, _d = /}/g.test(_t) ? _t.match(/}/g).length : 0; var _t1 = _t.replace(/{{/g, '{').replace(/}}/g, '}'); var _single = _c % 2 != 0 || _d % 2 != 0; if (!isNaN(idx)) { var _v = _tv._formatNumber(vals[idx], err); if (typeof _v == 'boolean' && !_v) { return false; } if (/^-\d$/g.test(_tv) && _single) { throw new Error(err[0]); } else if (idx >= len) { throw new Error(err[1]); } else if (_v == null) { throw new Error(err[2]); } rst.push(s.substr(0, _p) + (_c > 1 ? (_c % 2 != 0 ? _t1.replace('{' + idx + '}', _v) : _t1) : _v)); } else if (_single) { throw new Error(err[0] + '01'); } else { rst.push(_t1); } s = s.substr(_p + _t.length); } rst.push(s); return rst.join(''); } return s; }; String.prototype._formatNumber = function (_v, err) { var _tv = this; if (/[:]/g.test(_tv)) { var _sc = _tv.match(/(:)/g).length; if (_sc == 1) { var _ss = _tv.split(':')[1]; if (typeof _v == 'number') { var _p1 = /([CDEFG])/ig, _p2 = /([A-Z])/ig,_p3 = /^([CDEFG][\d]+)$/ig, _p4 = /^([A-Z]{1}[\d]+)$/ig; if ((_ss.length == 1 && _p1.test(_ss))||(_ss.length >= 2 && _p3.test(_ss))){ var _f1 = _ss.substr(0, 1), _f = _f1.toUpperCase(); var _n = parseInt(_ss.substr(1), 10)||(_f=='D'?0:2), _dn = ('' + _v).split('.'); _v = (''+_v)._formatNumberSwitch(_f1, _f, _n, _dn); } else if((_ss.length == 1 && _p2.test(_ss)) || (_ss.length >= 2 && _p4.test(_ss))){ throw new Error(err[3]); return false; } else if(/([0]+)/g.test(_ss)){ var _nv = Math.round(_v, 10), _arv = _ss.split(''), _arn = (''+_nv).split(''); _v = _tv._formatNumberZero(_arv, _arn); } else { _v = _ss; } } } else { if (typeof _v == 'number') { var _nv = Math.round(_v, 10),_pos = _tv.indexOf(':'), _arv = _tv.substr(_pos+1).split(''), _arn = (''+_nv).split(''); _v = _tv._formatNumberZero(_arv, _arn); } else{ _v = _tv.substr(_tv.indexOf(':') + 1); } } } return _v; }; String.prototype._formatNumberSwitch = function(_f1, _f, _n, _dn){ var _v = this; if(_dn[1]==undefined && (_f=='C'||_f=='F')){ _dn[1] = ''; _v += _n > 0 ? '.' : ''; } switch (_f) { case 'C': _vc = '¥' + _v; var _m = _dn[0].length % 3; if (_dn[0].length > 3) { _v = _vc.substr(0, _m + 1); var _pos = _m + 1; while (_pos < _dn[0].length - 1) { _v += ',' + _vc.substr(_pos, 3); _pos += 3; } _v += _vc.substr(_pos); } else { _v = _vc; } for (var i = 0, c = _n - (_dn[1]).length; i < c; i++) {_v += '0';} break; case 'D': if (/([.])/g.test(_v)) { throw new Error(err[3]); return false; } for (var i = 0, c = _n - (''+_v).length; i < c; i++) {_v = '0' + _v;} break; case 'E': var _n = _dn[0].length - 1, _fn = parseInt(('' + _v).substr(0, 1), 10), _num = Math.pow(10, _n), _e = Math.pow(10, 5); var _cn = (Math.round((_v - _num) / _num * _e) / _e + '').split('.')[1],_ln = ''; for (var i = ('' + _cn).length; i < 5; i++) {_cn += '0';} for (var i = ('' + _n).length; i < 3; i++) {_n = '0' + _n;} _v = _fn + '.' + _cn + _f1 + '+' + _n; break; case 'F': for (var i = 0, c = _n - _dn[1].length; i < c; i++) {_v += '0';} break; } return _v; }; String.prototype._formatNumberZero = function(_arv, _arn){ var _arr = [], _idx = _arn.length -1; for(var i=_arv.length-1; i>=0;i--){ _arr.push(_arv[i]=='0' ? (_idx >=0 ? _arn[_idx] : _arv[i]) : (function(){++_idx;return _arv[i];})()); _idx--; } for(var i=_idx; i>=0; i--){_arr.push(_arn[i]);} _arr = _arr.reverse (); return _arr.join(''); }; //demo var str = '你好:{0}，这是用{0}写的一个仿C#的{1}函数'; console.log(str.format2(['JS','format'])); console.log(str.format2('JS','format')); console.log("{0}{{正则{0:C5}{{表达式}}{1:F4}".format2(123.5, 12.5)) console.log("{0}{{正则{0:E5}{{表达式}}{1:0D12}".format2(123.5, 2)) console.log("{0:00:00:00}".format2(1234567)); console.log("{0:0000-00-00 00:00:00}".format2(20160824172215)); console.log("{0:0000年00月00日 00:00:00}".format2(20160824172215)); console.log("{0:0DF5}".format2(1234567));