May 2008
Intermediate to advanced
172 pages
4h 54m
English
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Invocation
Invoking a function suspends the execution of the current function, passing
control and parameters to the new function. In addition to the declared parameters,
every function receives two additional parameters: this and arguments. The this parameter is very important in object oriented
programming, and its value is determined by the invocation
pattern. There are four patterns of invocation in JavaScript: the
method invocation pattern, the function invocation pattern, the constructor
invocation pattern, and the apply invocation pattern. The patterns differ in how the
bonus parameter this is initialized.
The invocation operator is a pair of parentheses that follow any expression that
produces a function value. The parentheses can contain zero or more expressions,
separated by commas. Each expression produces one argument value. Each of the
argument values will be assigned to the function's parameter names. There is no
runtime error when the number of arguments and the number of parameters do not
match. If there are too many argument values, the extra argument values will be
ignored. If there are too few argument values, the undefined value will be substituted for the missing values. There is
no type checking on the argument values: any type of value can be passed to any
parameter.
The Method Invocation Pattern
When a function is stored as a property of an object, we call it a
method. When a method is invoked, this is bound to that object. If an invocation expression contains ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.