Monkey-patch (hook) functions for debugging and stuff.
npm install hookerMonkey-patch (hook) functions for debugging and stuff.
This code should work just fine in Node.js:
First, install the module with: npm install hooker
``javascript`
var hooker = require('hooker');
hooker.hook(Math, "max", function() {
console.log(arguments.length + " arguments passed");
});
Math.max(5, 6, 7) // logs: "3 arguments passed", returns 7
Or in the browser:
`html`
In the browser, you can attach Hooker's methods to any object.
`html`
####
The optional argument can be a method name, array of method names or null. If null (or omitted), all enumerable methods of object will be hooked.
#### options
* - (Function) a pre-hook function to be executed before the original function. Arguments passed into the method will be passed into the pre-hook function as well.
* post - (Function) a post-hook function to be executed after the original function. The original function's result is passed into the post-hook function as its first argument, followed by the method arguments.
* once - (Boolean) if true, auto-unhook the function after the first execution.
* passName - (Boolean) if true, pass the name of the method into the pre-hook function as its first arg (preceding all other arguments), and into the post-hook function as the second arg (after result but preceding all other arguments).#### Returns:
An array of hooked method names.
$3
Un-monkey-patch (unhook) one or more methods of an object.
#### Signature:
hooker.unhook(object [, props ])
####
The optional argument can be a method name, array of method names or null. If null (or omitted), all methods of object will be unhooked.
#### Returns:
An array of unhooked method names.$3
Get a reference to the original method from a hooked function.
#### Signature:
hooker.orig(object, props)$3
When a pre- or post-hook returns the result of this function, the value
passed will be used in place of the original function's return value. Any
post-hook override value will take precedence over a pre-hook override value.
#### Signature:
$3
When a pre-hook returns the result of this function, the value passed will
be used in place of the original function's return value, and the original
function will NOT be executed.
#### Signature:
$3
When a pre-hook returns the result of this function, the context and
arguments passed will be applied into the original function.
#### Signature:
Examples
See the unit tests for more examples.javascript
var hooker = require('hooker');
// Simple logging.
hooker.hook(Math, "max", function() {
console.log(arguments.length + " arguments passed");
});
Math.max(5, 6, 7) // logs: "3 arguments passed", returns 7hooker.unhook(Math, "max"); // (This is assumed between all further examples)
Math.max(5, 6, 7) // 7
// Returning hooker.override(value) overrides the original value.
hooker.hook(Math, "max", function() {
if (arguments.length === 0) {
return hooker.override(9000);
}
});
Math.max(5, 6, 7) // 7
Math.max() // 9000
// Auto-unhook after one execution.
hooker.hook(Math, "max", {
once: true,
pre: function() {
console.log("Init something here");
}
});
Math.max(5, 6, 7) // logs: "Init something here", returns 7
Math.max(5, 6, 7) // 7
// Filter
this and arguments through a pre-hook function.
hooker.hook(Math, "max", {
pre: function() {
var args = [].map.call(arguments, function(num) {
return num * 2;
});
return hooker.filter(this, args); // thisValue, arguments
}
});
Math.max(5, 6, 7) // 14// Modify the original function's result with a post-hook function.
hooker.hook(Math, "max", {
post: function(result) {
return hooker.override(result * 100);
}
});
Math.max(5, 6, 7) // 700
// Hook every Math method. Note: if Math's methods were enumerable, the second
// argument could be omitted. Since they aren't, an array of properties to hook
// must be explicitly passed. Non-method properties will be skipped.
// See a more generic example here: http://bit.ly/vvJlrS
hooker.hook(Math, Object.getOwnPropertyNames(Math), {
passName: true,
pre: function(name) {
console.log("=> Math." + name, [].slice.call(arguments, 1));
},
post: function(result, name) {
console.log("<= Math." + name, result);
}
});
var result = Math.max(5, 6, 7);
// => Math.max [ 5, 6, 7 ]
// <= Math.max 7
result // 7
result = Math.ceil(3.456);
// => Math.ceil [ 3.456 ]
// <= Math.ceil 4
result // 4
``_Also, please don't edit files in the "dist" subdirectory as they are generated via grunt. You'll find source code in the "lib" subdirectory!_