在使用Generator(生成器)函数做异步时,先引入协程这个概念,可以理解为 "协作的函数",一个协程本质就是子函数,不过这个子函数可以执行到一半,可以暂停执行,将执行权交给其他子函数,等稍后回收执行权的时候,还可以继续执行,跟线程非常像,在c++/python/java中一个线程的单位也是一个子函数(java的run方法),线程之间的切
3、迭代器(Generator) 迭代器是一个拥有{value:{*}, done:{Boolean}} next([*])方法 和 {undefined} throw([*])方法 的对象,通过next函数不断执行以关键字yield分割的代码段,通过throw函数令yield分割的代码段抛出异常。 三、核心1——迭代器 迭代器更多的是指迭代器模式,迭代器模式是指通过一个名为迭代...
functiongenerator() {vari = 0;returnfunction() {returni++; }; }vargen1 = generator();//得到一个自然数生成器vargen2 = generator();//得到另一个自然数生成器varr1 = gen1();//r1 = 0varr2 = gen1();//r2 = 1varr3 = gen2();//r3 = 0varr4 = gen2();//r4 = 1 上面的代码展...
Calling the generator function returns an iterator. When the iterator'snextmethod is called, the generator function's body is executed until the firstyieldexpression; it returns an object with avalueproperty containing the yielded value. Thedoneproperty indicates whether the generator has yielded its ...
第一次看koajs的示例时,发现该语句function *(next){...},这是啥啊?于是搜索一下,原来这是就是ES6的新特性Generator Function(生成器函数)。 那什么是生成器函数呢?其实就相当于C#2.0中通过yield关键字实现的迭代器的生成器(细节有所不同),那么理解的关键就在迭代器和yield关键字两部分了。下面将尝试从表象...
第一次调用Generator函数,返回遍历器对象。这时候,函数内部是没有执行的,仅仅返回遍历器对象。当调用next()方法时,函数才从头部开始执行,直到遇到yield表达式,则交出函数执行权,函数停止执行。 每次调用next方法,内部指针就从函数头部或上一次停下来的地方开始执行,直到遇到下一个yield表达式(或return语句)为止。
Determine if a function is a native generator function.. Latest version: 1.1.0, last published: 5 months ago. Start using is-generator-function in your project by running `npm i is-generator-function`. There are 768 other projects in the npm registry usi
is no syntactic means to create instances of Function subclasses except for the built-in Generator...
== 'function') throw new TypeError('middleware must be a function!'); if (isGeneratorFunction(fn)) { deprecate('Support for generators will be removed in v3. ' + 'See the documentation for examples of how to convert old middleware ' + 'https://github.com/koajs/koa/blob/master/docs...
The function generator includes a variable gain controller section coupled to a proximity sensing motion balance servomechanism which varies the gain of the controller according to the sensed proximity of the servomechanism to the edge of the cam member without physical contact therewith. The cam ...