JStalker

This script is an improvement of Eligrey's awesome Object.watch().js script

Basically, he did all the hard work, I forked the script and made it more good-looking with more functions, but still props to him, I would never do this alone because I'm still pretty much a newbie

Installation

<script src="jstalker.js"></script> at the end of your HTML and you're ready to go !!

Getting started

All the functions are defined as properties of Object, so you just call them from your object like this: obj.function(args)

All variable changes called from inside a function will output the calling function.

Example:

var obj = {id: 5};
obj.watch('obj','id');
function testFunc() {
  obj.id = 12;
}

will output

>>> JStalker.watch()
> Called by function testFunc()
- obj.id changed: 5 -> 12

Note: This won't work if you declare your function like this:

var testFunc = function() {
  obj.id = 12;
}

The first parameter obj

All functions have the same first parameter obj in their declarations / calls. It names the obj containing the variable you want to watch ( you can put anything you want it's not important, it's just used to ouput obj.variable in the console so if you put somethingSilly it will output somethingSilly.variable )

Important note

Each of these functions are actually Object properties redefining the set() function to trigger a message if you modify the value of the specified variable.

Because of this, you can't apply multiple stalkers to a single variable because you would then redefine the set() function each time, and so only the last one will actually work.

In short,

var obj = {n: 5};
obj.watch('obj','n');
obj.isEqual('obj','n',8);
obj.isNull('obj','n');

is equal to

obj.isNull('obj','n');

Functions

obj.watch(obj, var)

Parameters

• obj: See here
• var: The variable you want to stalk

This function will output a message in the console each time the value of the specified variable changes

Example

var obj = { val1: 5, val2: 7};
obj.watch('obj','val1');
obj.val1 = 6; // will trigger the message here
obj.val2 = 10; // val 2 not watched so will not trigger anything

will output

>>> JStalker.watch()
- obj.val1 changed: 5 -> 6

obj.isEqual(obj, var, val)

Parameters

• obj: See here
• var: The variable you want to stalk
• val: The triggering value

The function will output a message in the console when the specified variable is equal to the given value

Example

var obj = {var: 1, msg: 'Hi'};
obj.isEqual('obj','msg','Hello world');
obj.msg = 'Hello guys';
obj.msg = 'Hello world'; // Will trigger the output
obj.msg = 'Hi bro';

will output

>>> JStalker.isEqual()
- obj.msg is equal to Hello world

obj.isNull(obj, var)

Parameters

• obj: See here
• var: The variable you want to stalk

The function will output a message in the console when the specified variable is equal to undefined or null

Example

var obj = {n: 5};
obj.isNull('obj','n');
obj.n = null; // Will trigger a message
obj.n = undefined; // Will also trigger a message

will output

>>> JStalker.isNull()
- obj.n is null
>>> JStalker.isNull()
- obj.n is undefined

obj.isInRange(obj, var, min, max)

Parameters

• obj: See here
• var: The variable you want to stalk
• min: The minimum value of the range
• max: The maximum value of the range

The function will output a message if the specified variable is inside the given range

Example

var obj = {r: 7};
obj.isInRange('obj','r',10,20);
obj.r = 8;
obj.r = 15; // Will trigger a message

will output

>>> JStalker.isInRange()
- obj.r is between 10 and 20 ( Value: 15 )

obj.isOutOfRange(obj, var, min, max)

Parameters

• obj: See here
• var: The variable you want to stalk
• min: The minimum value of the range
• max: The maximum value of the range

The nemesis of obj.isInRange(), this function will output a message if the specified variable is outside of the given range

Example

var obj = {s: 25};
obj.isOutOfRange('obj','s',10,20);
obj.s = 8; // Will trigger a message
obj.s = 15;
obj.s = 22; // Will also trigger a message

will output

>>> JStalker.isOutOfRange()
- obj.s is outside of the range [ 10 - 20 ] Value: 8
>>> JStalker.isOutOfRange()
- obj.s is outside of the range [ 10 - 20 ] Value: 22