Notes on software and the ideas behind it
Find the meaning
behind the code.
I’m Fred Yang. I write about software—how it works, why it behaves the way it does, and the ideas that make code easier to reason about.
Open the notebookWorking notes / 2026
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Architecture, reactivity, and the hidden relationships that shape frontend systems.
jquery
shadow copy in jQuery
We can use jQuery to copy(clone) an object to a new object, so the old object and the new object can evolved independently. //shadow copy object var oldObj = { name: "fred" }; var...
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javascript
copy array in javascript
var x = [1, 2];
var y = x.slice(0);
y[0] = 100; //y --> [100, 2]
alert(x[0]); //1
The new copy evolve independently of the old copy.
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jquery
Easy Setter Functions in jquery
One of the new feature in jQuery 1.4 is setter function. For a while now, you’ve been able to pass a function into .attr() and the return value of that function is set into...
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javascript
how to test whether a object has member
Object.prototype.hasMember = function (memberName)
{
return memberName in this;
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jquery
how jQuery use sizzle selector
The call stack is as follow <pre data-sub="prettyprint:_">return new jQuery.fn.init( selector, context );
return (context || rootjQuery).find( selector );
jQuery.find( selector, this[i], ret );
return makeArray(context.querySelectorAll(query), extra );
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