Underscore.js templates as a standalone implementation

underscore-1.3.3-templates.js

/*!
    Underscore.js templates as a standalone implementation. 
    JavaScript micro-templating, similar to John Resig's implementation. 
    Underscore templates documentation: http://documentcloud.github.com/underscore/#template
    Modifyed by marlun78
*/
(function () {

    'use strict';

    // By default, Underscore uses ERB-style template delimiters, change the
    // following template settings to use alternative delimiters.
    var settings = {
        evaluate: /<%([\s\S]+?)%>/g,
        interpolate: /<%=([\s\S]+?)%>/g,
        escape: /<%-([\s\S]+?)%>/g
    };

    // When customizing `templateSettings`, if you don't want to define an
    // interpolation, evaluation or escaping regex, we need one that is
    // guaranteed not to match.
    var noMatch = /.^/;

    // Certain characters need to be escaped so that they can be put into a
    // string literal.
    var escapes = {
        '\\': '\\',
        "'": "'",
        'r': '\r',
        'n': '\n',
        't': '\t',
        'u2028': '\u2028',
        'u2029': '\u2029'
    };

    for (var p in escapes) {
        escapes[escapes[p]] = p;
    }

    var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;
    var unescaper = /\\(\\|'|r|n|t|u2028|u2029)/g;

    var tmpl = function (text, data, objectName) {
        settings.variable = objectName;

        // Compile the template source, taking care to escape characters that
        // cannot be included in a string literal and then unescape them in code
        // blocks.
        var source = "__p+='" + text
            .replace(escaper, function (match) {
                return '\\' + escapes[match];
            })
            .replace(settings.escape || noMatch, function (match, code) {
                return "'+\n_.escape(" + unescape(code) + ")+\n'";
            })
            .replace(settings.interpolate || noMatch, function (match, code) {
                return "'+\n(" + unescape(code) + ")+\n'";
            })
            .replace(settings.evaluate || noMatch, function (match, code) {
                return "';\n" + unescape(code) + "\n;__p+='";
            }) + "';\n";

        // If a variable is not specified, place data values in local scope.
        if (!settings.variable) {
            source = 'with(obj||{}){\n' + source + '}\n';
        }

        source = "var __p='';var print=function(){__p+=Array.prototype.join.call(arguments, '')};\n" + source + "return __p;\n";

        var render = new Function(settings.variable || 'obj', source);

        if (data) {
            return render(data);
        }

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

        // Provide the compiled function source as a convenience for build time
        // precompilation.
        template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';

        return template;
    };

    window.tmpl = tmpl;

}());