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Deno 2.2 Improves Dependency Management and Expands Node.js Compatibility
Deno 2.2 enhances Node.js compatibility, improves dependency management, adds OpenTelemetry support, and expands linting and task automation for developers.
eventproxy
Advanced tools
这个世界上不存在所谓回调函数深度嵌套的问题。 —— Jackson Tian
世界上本没有嵌套回调,写得人多了,也便有了
}}}}}}}}}}}}
。 -- fengmk2
EventProxy 仅仅是一个很轻量的工具,但是能够带来一种事件式编程的思维变化。有几个特点:
现在的,无深度嵌套的,并行的
var ep = EventProxy.create("template", "data", "l10n", function (template, data, l10n) {
_.template(template, data, l10n);
});
$.get("template", function (template) {
// something
ep.emit("template", template);
});
$.get("data", function (data) {
// something
ep.emit("data", data);
});
$.get("l10n", function (l10n) {
// something
ep.emit("l10n", l10n);
});
过去的,深度嵌套的,串行的。
var render = function (template, data) {
_.template(template, data);
};
$.get("template", function (template) {
// something
$.get("data", function (data) {
// something
$.get("l10n", function (l10n) {
// something
render(template, data, l10n);
});
});
});
The callback will be executed once when all event were fired.
<script src="https://raw.github.com/JacksonTian/eventproxy/master/lib/eventproxy.js"></script>
<script>
var render = function (template, data, l10n) {
_.template(template, data, l10n);
};
var ep = EventProxy.create("template", "data", "l10n", render);
$.get("template", function (template) {
// something
ep.emit("template", template);
});
$.get("data", function (data) {
// something
ep.emit("data", data);
});
$.get("l10n", function (l10n) {
// something
ep.emit("l10n", l10n);
});
</script>
The callback will be executed first time when all event were fired. And after that, any event was fired will trigger callback. It's useful when you need refresh UI with newest data, e.g. stock app.
<script src="https://raw.github.com/JacksonTian/eventproxy/master/lib/eventproxy.js"></script>
<script>
var render = function (template, data, l10n) {
_.template(template, data, l10n);
};
var ep = EventProxy.create();
ep.assignAll("template", "dataUpdate", "l10n", render);
$.get("template", function (template) {
// something
proxy.emit("template", template);
});
$.get("l10n", function (l10n) {
// something
proxy.emit("l10n", l10n);
});
// Need refresh data and UI for some realtime application.
setInterval(function () {
$.get("data", function (data) {
// something
proxy.emit("dataUpdate", data);
});
}, 1000);
</script>
$ npm install eventproxy
Sample code:
var eventproxy = require("eventproxy");
var ep = eventproxy.create("template", "data", "l10n", function (template, data, l10n) {
return _.template(template, data);
});
$.get("template", function (template) {
// something
proxy.emit("template", template);
});
$.get("data", function (data) {
// something
proxy.emit("data", data);
});
$.get("l10n", function (l10n) {
// something
proxy.emit("l10n", l10n);
});
这是来自我们实践代码总结,通过 error
事件统一处理所有异步请求的异常。
var eventproxy = require('eventproxy');
exports.getTweet = function (userId, tweetId, callback) {
// eventproxy.create(events, handler, errorHandler);
var ep = eventproxy.create('user', 'tweet', 'retweets', 'friends', 'messages',
function (user, tweet, retweets, friends, messages) {
user.friends = friends;
user.messages = messages;
tweet.user = user;
tweet.retweets = retweets;
callback(null, tweet);
}, function (err) {
callback(err);
});
// or you can use `ep.fail(errorHandler)` to listen 'error' event.
twitter.get(tweetId, ep.done('tweet'));
twitter.getRetweets(tweetId, ep.done('retweets'));
twitter.getUser(userId, ep.done(function (user) {
ep.emit('user', user);
twitter.getUserFriends(user.id, ep.done('friends'));
}));
twitter.getUserMessages(userId, ep.done('message'));
};
在没使用上述方法前,我们会这样写代码:
var eventproxy = require('eventproxy');
exports.getTweet = function (userId, tweetId, callback) {
// eventproxy.create(events, handler);
var ep = eventproxy.create('user', 'tweet', 'retweets', 'friends', 'messages',
function (user, tweet, retweets, friends, messages) {
user.friends = friends;
user.messages = messages;
tweet.user = user;
tweet.retweets = retweets;
callback(null, tweet);
});
ep.once('error', function (err) {
ep.unbind();
callback(err);
});
twitter.get(tweetId, function (err, tweet) {
if (err) {
return ep.emit('error', err);
}
ep.emit('tweet', tweet);
});
twitter.getRetweets(tweetId, function (err, retweets) {
if (err) {
return ep.emit('error', err);
}
ep.emit('retweets', retweets);
});
twitter.getUser(userId, function (err, user) {
if (err) {
return ep.emit('error', err);
}
ep.emit('user', user);
twitter.getUserFriends(user.id, function (err, friends) {
if (err) {
return ep.emit('error', err);
}
ep.emit('friends', friends);
});
});
twitter.getUserMessages(userId, function (err, messages) {
if (err) {
return ep.emit('error', err);
}
ep.emit('messages', messages);
});
};
请勿使用all
作为业务中的事件名。该事件名为保留事件。
(The MIT License)
FAQs
An implementation of task/event based asynchronous pattern.
The npm package eventproxy receives a total of 7,242 weekly downloads. As such, eventproxy popularity was classified as popular.
We found that eventproxy demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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