13. 问题：异步协作
var proxy = new EventProxy();
•
proxy.all("template", "data", "l10n", render);
嵌套还是并行？
$.get("template", function (template) {
// something
$.get("template", function (template) {
proxy.trigger("template", template);
}); // something
$.get("data", function (data) { {
$.get("data", function (data)
// something
// something
$.get("l10n", function (l10n) {
proxy.trigger("data", data);
}); // something
render(template, data);
$.get("l10n", function (l10n) {
});
// something
});
proxy.trigger("l10n", l10n);
});
});
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14. 问题：异步还是同步
var proxy = new EventProxy();
var status = "ready";
• 复杂的异步编程
var _getFile = function (callback) {
proxy.once("template", callback);
if (status === "ready") {
fs.readFile("views/index.html", function (err, file) {
status = "pending";
proxy.fire("template", err, file);
});
}
};
var view = fs.readFileSync("../views/index.html", "utf8");
var _template;
var getTemplate = function (callback) {
if (_template) {
callback(null, _template);
} else {
同步 + 缓存，妥妥滴
_getFile(function (err, file) {
if (!err && !_template) {
_template = file.toString();
}
callback(null, _template);
});
}
};
14
15. 问题：缓存的使用
var map = {};
var get = function (key) {
var LimitableMap = require('limitablemap');
return map[key];
}; map = new LimitableMap(1000);
var
map.set("key1", "key1");
var set = function (key, value) {
map.get("key1");
map[key] = value;
};
// 检查缓存
if (!get(key)) {
// 从数据库或别的地方获取了对象后，放进缓存中
set(key, value);
}
15
17. // 正确的方法
var chunks = [];
var size = 0;
问题：Buffer对象
res.on('data', function (chunk) {
chunks.push(chunk);
size += chunk.length;
});
var data = "";
res.on('end', function () {
res.on('data', function (chunk) {
var data = null;
//switch(chunks.length) {
// chunk是⼀一个Buffer对象
简单且正确的方法
data 0: data = new =隐藏的toString（）
case += chunk;//Buffer(0);
var break;
bufferHelper new BufferHelper();
}) case 1: data = function
req.on("data",chunks[0]; (chunk) {
.on("end", function () {
bufferHelper.concat(chunk);
break;
})//对data转码
default:
.on('end',new Buffer(size);
}); data = function () {
for (var i = 0, pos = 0, l = chunks.length; i < l; i++) {
varvar chunk bufferHelper.toBuffer().toString();
html = = chunks[i];
}); chunk.copy(data, pos);
pos += chunk.length;
}
break;
}
}); 17
