handlebars.js -- Uncertain number of attributes object traversal

handlebars-eachobj.js

/**
 * handlebars eachObj
 * User: Nightink
 * Date: 13-08-23
 */
 
define(function(require, exports, module) {
    var handlebars = require('handlebars');
 
    function isFunction(value) {
        return Object.prototype.toString.call(value) === '[object Function]';
    }
 
    /**
     * count = null; The default is null iterate through all properties.
     * var obj = {name: '', age: ''};
     * {{#eachObj obj count}}
     * <tr>
     * <td>properties：{{prop}}</td>
     * <td>value：{{val}}</td>
     * </tr>
     * {{/each}}
     */
    handlebars.registerHelper('eachObj', function(obj, count, options) {
        // options.fn is handlebars.js template parsing and generating function parameter substitution.
        var html = [], i = 0;
        if(isFunction(count)) {
            options = count;
            count = 0;
        }
        for(var key in obj) {
            if(count && i >= count) {
                break;
            }
 
            html.push(options.fn({
                prop: key,
                val: obj[key]
            }));
            i++;
        }
        return html.join('');
    });
});


// var options = {
//     fn: [function],      // 模板解析生成函数
//     inverse: [function]
// };

// obj 是模板需要解析的对象 options 为handlebars自身对模板的解析函数和关于的配置参数
// 对性能有一定的提升