underscore_TemplateEngine.js

'use strict';

window._ = {};

_.templateSettings = {
    evaluate: /<%([\s\S]+?)%>/g,
    interpolate: /<%=([\s\S]+?)%>/g,
    escape: /<%-([\s\S]+?)%>/g
};

var escapes = {
    "'": "'",
    '\\': '\\',
    '\r': 'r',
    '\n': 'n',
    '\u2028': 'u2028',
    '\u2029': 'u2029'
};

var escapeRegExp = /\\|'|\r|\n|\u2028|\u2029/g;
var matcher = RegExp([
        (_.templateSettings.escape).source,
        (_.templateSettings.interpolate).source,
        (_.templateSettings.evaluate).source
    ].join('|') + '|$', 'g');

var escapeChar = function (match) {
    return '\\' + escapes[match];
};

_.template = function (text) {

    var index = 0;
    var source = "__p+='";
    text.replace(matcher, function (match, escape, interpolate, evaluate, offset) {
        source += text.slice(index, offset).replace(escapeRegExp, escapeChar);
        index = offset + match.length;

        if (escape) {
            source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
        }
        else if (interpolate) {
            source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
        }
        else if (evaluate) {
            source += "';\n" + evaluate + "\n__p+='";
        }

        return match;
    });
    source += "';\n";

    source = 'with(obj){\n' + source + '}\n';
    source = "var __t,__p='',__j=Array.prototype.join;\n" +
        source + 'return __p;\n';

    var render = new Function('obj', '_', source);

    var template = function (data) {
        return render.call(this, data, _);
    };
    
    return template;
};