underscore.js 964 --- 1103行

今天剩下的大部分都是工具函数了，比较易读，就过一遍即可

// Keys in IE < 9 that won't be iterated by `for key in ...` and thus missed.var hasEnumBug = !{toString: null}.propertyIsEnumerable('toString');var nonEnumerableProps = ['valueOf', 'isPrototypeOf', 'toString','propertyIsEnumerable', 'hasOwnProperty', 'toLocaleString'];var collectNonEnumProps = function(obj, keys) {var nonEnumIdx = nonEnumerableProps.length;var constructor = obj.constructor;var proto = _.isFunction(constructor) && constructor.prototype || ObjProto;// Constructor is a special case.var prop = 'constructor';if (_.has(obj, prop) && !_.contains(keys, prop)) keys.push(prop);while (nonEnumIdx--) {prop = nonEnumerableProps[nonEnumIdx];if (prop in obj && obj[prop] !== proto[prop] && !_.contains(keys, prop)) {keys.push(prop);}}};// Retrieve the names of an object's own properties.// Delegates to **ECMAScript 5**'s native `Object.keys`._.keys = function(obj) {if (!_.isObject(obj)) return [];if (nativeKeys) return nativeKeys(obj);var keys = [];for (var key in obj) if (_.has(obj, key)) keys.push(key);// Ahem, IE < 9.if (hasEnumBug) collectNonEnumProps(obj, keys);return keys;};// Retrieve all the property names of an object._.allKeys = function(obj) {if (!_.isObject(obj)) return [];var keys = [];for (var key in obj) keys.push(key);// Ahem, IE < 9.if (hasEnumBug) collectNonEnumProps(obj, keys);return keys;};// Retrieve the values of an object's properties._.values = function(obj) {var keys = _.keys(obj);var length = keys.length;var values = Array(length);for (var i = 0; i < length; i++) {values[i] = obj[keys[i]];}return values;};// Returns the results of applying the iteratee to each element of the object.// In contrast to _.map it returns an object._.mapObject = function(obj, iteratee, context) {iteratee = cb(iteratee, context);var keys = _.keys(obj),length = keys.length,results = {};for (var index = 0; index < length; index++) {var currentKey = keys[index];results[currentKey] = iteratee(obj[currentKey], currentKey, obj);}return results;};// Convert an object into a list of `[key, value]` pairs.// The opposite of _.object._.pairs = function(obj) {var keys = _.keys(obj);var length = keys.length;var pairs = Array(length);for (var i = 0; i < length; i++) {pairs[i] = [keys[i], obj[keys[i]]];}return pairs;};// Invert the keys and values of an object. The values must be serializable._.invert = function(obj) {var result = {};var keys = _.keys(obj);for (var i = 0, length = keys.length; i < length; i++) {result[obj[keys[i]]] = keys[i];}return result;};// Return a sorted list of the function names available on the object.// Aliased as `methods`._.functions = _.methods = function(obj) {var names = [];for (var key in obj) {if (_.isFunction(obj[key])) names.push(key);}return names.sort();};// An internal function for creating assigner functions.var createAssigner = function(keysFunc, defaults) {return function(obj) {var length = arguments.length;if (defaults) obj = Object(obj);if (length < 2 || obj == null) return obj;for (var index = 1; index < length; index++) {var source = arguments[index],keys = keysFunc(source),l = keys.length;for (var i = 0; i < l; i++) {var key = keys[i];if (!defaults || obj[key] === void 0) obj[key] = source[key];}}return obj;};};// Extend a given object with all the properties in passed-in object(s)._.extend = createAssigner(_.allKeys);

collectNonEnumProps

// Keys in IE < 9 that won't be iterated by `for key in ...` and thus missed.var hasEnumBug = !{toString: null}.propertyIsEnumerable('toString'); // 是否存在小于ie9的无法for in的bugvar nonEnumerableProps = ['valueOf', 'isPrototypeOf', 'toString','propertyIsEnumerable', 'hasOwnProperty', 'toLocaleString']; var collectNonEnumProps = function(obj, keys) {var nonEnumIdx = nonEnumerableProps.length;var constructor = obj.constructor;var proto = _.isFunction(constructor) && constructor.prototype || ObjProto;// Constructor is a special case.var prop = 'constructor';if (_.has(obj, prop) && !_.contains(keys, prop)) keys.push(prop);while (nonEnumIdx--) {prop = nonEnumerableProps[nonEnumIdx];if (prop in obj && obj[prop] !== proto[prop] && !_.contains(keys, prop)) {keys.push(prop);}}};

收集对象中无法迭代的属性

_.keys

 // Retrieve the names of an object's own properties.// Delegates to **ECMAScript 5**'s native `Object.keys`._.keys = function(obj) {if (!_.isObject(obj)) return []; // 如果非对象，返回空数组if (nativeKeys) return nativeKeys(obj); // object.keysvar keys = []; for (var key in obj) if (_.has(obj, key)) keys.push(key); // 原生属性迭代，非prototype// Ahem, IE < 9.if (hasEnumBug) collectNonEnumProps(obj, keys);return keys; };// Retrieve all the property names of an object._.allKeys = function(obj) {if (!_.isObject(obj)) return [];var keys = [];for (var key in obj) keys.push(key);// Ahem, IE < 9.if (hasEnumBug) collectNonEnumProps(obj, keys);return keys;}; //包含prototype

_.values

// Retrieve the values of an object's properties._.values = function(obj) {var keys = _.keys(obj);var length = keys.length;var values = Array(length);for (var i = 0; i < length; i++) {values[i] = obj[keys[i]];}return values;};

收集value，且是原生

_.mapObject

 // Returns the results of applying the iteratee to each element of the object.// In contrast to _.map it returns an object._.mapObject = function(obj, iteratee, context) {iteratee = cb(iteratee, context);var keys = _.keys(obj),length = keys.length,results = {};for (var index = 0; index < length; index++) {var currentKey = keys[index];results[currentKey] = iteratee(obj[currentKey], currentKey, obj);}return results;};

已解释

_.pairs

 // Convert an object into a list of `[key, value]` pairs.// The opposite of _.object._.pairs = function(obj) {var keys = _.keys(obj); // 取得原生keyvar length = keys.length;var pairs = Array(length);for (var i = 0; i < length; i++) {pairs[i] = [keys[i], obj[keys[i]]];}return pairs;};

_.invert

// Invert the keys and values of an object. The values must be serializable._.invert = function(obj) {var result = {};var keys = _.keys(obj);for (var i = 0, length = keys.length; i < length; i++) {result[obj[keys[i]]] = keys[i];}return result;};

翻转

_.functions

// Return a sorted list of the function names available on the object.// Aliased as `methods`._.functions = _.methods = function(obj) {var names = [];for (var key in obj) {if (_.isFunction(obj[key])) names.push(key);}return names.sort();};

prototype的方法也会涉及

_.extend

 // An internal function for creating assigner functions.var createAssigner = function(keysFunc, defaults) {return function(obj) {var length = arguments.length;if (defaults) obj = Object(obj);if (length < 2 || obj == null) return obj;for (var index = 1; index < length; index++) {var source = arguments[index],  keys = keysFunc(source),l = keys.length;for (var i = 0; i < l; i++) {var key = keys[i];if (!defaults || obj[key] === void 0) obj[key] = source[key];}} // 拓展属性，如果设定default，则就按照原属性写入return obj;};};// Extend a given object with all the properties in passed-in object(s)._.extend = createAssigner(_.allKeys); //  区别在于一个覆写所有_.extendOwn = _.assign = createAssigner(_.keys);// 一个覆写原生

_.findKey

// Returns the first key on an object that passes a predicate test._.findKey = function(obj, predicate, context) {predicate = cb(predicate, context);var keys = _.keys(obj), key;for (var i = 0, length = keys.length; i < length; i++) {key = keys[i];if (predicate(obj[key], key, obj)) return key;}};

找到符合条件的key就跑路，返回key，正所谓跑得快

没了

underscore.js 964 --- 1103行相关推荐

underscore.js源码研究(5)
概述很早就想研究underscore源码了,虽然underscore.js这个库有些过时了,但是我还是想学习一下库的架构,函数式编程以及常用方法的编写这些方面的内容,又恰好没什么其它要研究的了,所以 ...
underscore.js源码整体框架解析
源码框架读一些库的源码时最头疼的其实不是里面各个函数的功能,而是整体结构框架,通常库的源码都很长,跟框架相关的代码并不是在一起放着的,导致你想明白起来就很困难. 我看过通过画图的方式去讲解框架的,但 ...
Underscore.js 入门教程
出处:http://web.jobbole.com/87537/ 总结: Underscore.js 是一个由 Jeremy Ashkenas 开发的 JavaScript 库,它提供了许多作为开发者 ...
Underscore.js 入门
Underscore封装了常用的JavaScript对象操作方法,用于提高开发效率.它本身与我们介绍的主题"Backbone"没有半毛钱的关系,因此你可以完全不理会"Ba ...
Underscore.js 初探
一. 简介 Underscore 这个单词的意思是"下划线". Underscore.js 是一个 JavaScript 工具库,提供了一整套的辅助方法供你使用. Think th ...
HTML怎么限制每行字数,JS实现每行固定字数，自动换行
JS实现每行固定字数,自动换行 autoWrap.html 原码 .wrap_focus{border-width: 3px;border-style: solid;border-color:oran ...
js 实现 table 行上移（数据库）
通过js实现表格行的上下移动,有两种情况: 1.只对显示层操作(即只针对页面的移动并不更新到数据库) 2.显示层的移动更新到数据库中下面我分布就这两种方式的实现进行说明(我使用的是jquery ea ...
Underscore.js常用方法介绍
Underscore.js是一个很精干的库,压缩后只有4KB.它提供了几十种函数式编程的方法,弥补了标准库的不足,大大方便了JavaScript的编程.MVC框架Backbone.js就将这个库作为自 ...
underscore.js 页面数据渲染
1.underscore.js 源码 // Underscore.js 1.8.3 // http://underscorejs.org // (c) 2009-2015 Jeremy Ashken ...
Underscore.js 的模板功能
Underscore是一个非常实用的JavaScript库,提供许多编程时需要的功能的支持,他在不扩展任何JavaScript的原生对象的情况下提供很多实用的功能. 无论你写一段小的js代码,还是写一 ...

underscore.js 964 --- 1103行

collectNonEnumProps

_.keys

_.values

_.mapObject

_.pairs

_.invert

_.functions

_.extend

_.findKey

underscore.js 964 --- 1103行相关推荐

最新文章

热门文章