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  Let's talk about JSON.stringify()

JSON has been used in lots of places to exchange data among different services/systems. Nowadays all mainstream programming languages have built-in library support of JSON data parse and stringify. In this post, let's talk about JSON.stringify() in JavaScript. Let's first take a small example of Object conversion handling. There is a requirement to convert below object const todayILearn = { _id: 1, content: '今天学习 JSON.stringify()，我很开心！', ...

   JAVASCIPT,JSON,JSON.STRINGIFY     2020-02-22 04:25:08

  Basic Mistakes Developers Make When Creating APIs

Today, there are many tools that developers can use to create an API, meaning that some of them can come up with an API within a matter of minutes. However, there is a vast difference between just creating an API and building one that meets all your expectations, is reliable and secure. Some developers create APIs that work well but forget some basic things that, within no time, bring a lot of issues to the API users. In this article, we are going to talk about the basic mistakes that developers...

   API,API DESIGN,RESTFUL API     2020-08-19 07:54:03

  Bug caused by using changeable value as the default in "python method overload"​

In python we can set the passed in parameter's default value to make the function has the same running feature as the method overload in Java. Define a function like this: def testFunction(self, param1, param2=None, param3=None): Normally we use "None" as the parameter's default value. We can also use str/bool as the default value, but is it OK we use empty list [] as its default value? This is our test program: """ A test program using empty list as the passed-in parameter's default value. ...

   PYTHON     2019-03-11 08:52:52

  The evolving history of asynchronous operation in JavaScript

JavaScript is single threaded, it means there would be only one task running at any point of time. But this would slow down the overall program execution if there is long running task, hence asynchronous task execution is desired in complex cases. To achieve asynchronous task execution, there are a few options introduced in JavaScript. setTimeout/setInterval Event Promise Async/Await setTimeout/setInterval is one of the first mechanisms introduced in JavaScript to simulate asynchronous operati...

   JAVASCRIPT,ASYNC,PROMISE,AWAIT     2019-11-09 08:21:56

  A plugin to update last_error in Delayed Job

delayed_job is a process based asynchronous task processing gem which can be ran at background. It will fork the specified number of processes to execute the tasks asynchronously. The task status is usually stored in the database so that it can be easily integrated into a Rails application where asynchronous job execution is desired. Normally when a job fails to execute or error occurs, it would save the error into the database with the column last_error. Ideally all these will be handled b...

   RUBY,RUBY ON RAILS,DELAYED JOB,LAST_ERROR     2017-11-18 13:05:49

  Error handling style in C

Following are three error handling styles in C.Which one you like the most? Or you don't like any one?1. /* Problem : Not enough. Easy to be wrong */int foo(int bar){        int return_value = 0;        int doing_okay = 1;        doing_okay = do_something( bar );        if (doing_okay)        { ...

   C,Error handling style,Goto,Nested if     2012-04-24 06:51:00

  About JavaScript source map

Last week jQuery 1.9 was released. This is the last release before jQuery 2.0. It adds many new functions, one of them is the source map. By accessing http://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js , you can scroll to the last line and you will see below line : 　//@ sourceMappingURL=jquery.min.map This is source map, it is a separate file and it is put at the same directory as the source file. You can click here and see what it looks like. It's an very useful functio...

   Source map, JavaScript, jQuery     2013-02-01 07:06:44

  A Tiny MySQL++ Tutorial; C++ and MySQL; MySQL++ Example

I wrote a post about how to install MySQL++ and I thought I will write a quick tutorial on how to use it too. This is a very basic MySQL++ program and it’s very self explanatory: #include <mysql++.h> #include <stdlib.h>   using namespace std; using namespace mysqlpp;   int main() { try { Connection conn(false); conn.connect("DB NAME", "DB HOST probably localhost", "DB USER", "DB PASS"); Query query = conn.query(); } catch (BadQuery er...

   C++,Example,MySQL++,Insert,API     2011-09-05 02:12:40

  How to write your own DSL in Ruby

DSL(Domain Specific Language) is a language defined to fulfill some domain specific requirements to ease people's work. It can be used to define attributes and actions of a domain easily and cleanly. And it is often created based on some common observations or micro patterns of some domain. In Ruby world, there are quite a few places people can find DSL. For example, Ruby itself, Chef recipes. To create a class in Ruby, the traditional OOP way would look like. class User @name = nil @email =...

   RUBY,DSL,TUTORIAL     2017-03-04 09:40:34

  Understanding lvalues and rvalues in C and C++

The terms lvalue and rvalue are not something one runs into often in C/C++ programming, but when one does, it’s usually not immediately clear what they mean. The most common place to run into these terms are in compiler error & warning messages. For example, compiling the following with gcc: int foo() {return 2;} int main() { foo() = 2; return 0; } You get: test.c: In function 'main': test.c:8:5: error: lvalue required as left operand of assignment True, this code ...

   lvalue,rvalue,C++,locator value,elaboration     2011-12-15 07:51:38

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