Created
December 4, 2011 07:16
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Javascripts - Ian Link
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/*------------------------------------------------------------------------------------ | |
* | |
* Bind from JSON - uses JSON to set up UI bindings. Utilizes jquery's 'bind' | |
* | |
* Usage: | |
* Supply JSON file formatted like this: | |
* var json = [{ | |
* 'selector' : '#id', | |
* 'bind_to' : 'click', | |
* 'func' : [ | |
* func1, | |
* func2 | |
* ] | |
* }]; | |
* | |
* Call the function: | |
* jsUtil.bind_from_json(json) | |
* | |
* Note that you can include any valid jquery selector or combination of selectors | |
* | |
* Changelog: | |
* | |
* Version 0.3: Better typechecking | |
* | |
* Version 0.2: Added support for binding to multiple functions | |
* - Better error reporting for type-checking errors | |
* | |
* Version 0.1: Initial commit | |
* | |
-----------------------------------------------------------------------------------*/ | |
if (typeof jsUtil === 'undefined'){ | |
var jsUtil = {}; | |
} | |
jsUtil.bind_from_json = function(json){ | |
"use strict"; | |
if(typeof json == 'undefined') return 'No json supplied' | |
for (var i = 0; i < json.length; i++){ | |
if (typeof json[i].selector !== 'string'){ | |
throw "Error in supplied JSON at index "+ i + ". Expects 'Selector' as String"; | |
} | |
if (typeof json[i].bind_to !== 'string'){ | |
throw "Error in supplied JSON at index "+ i + ". Expects 'Bind_to as String"; | |
} | |
if (json[i].hasOwnProperty('func')) { | |
if (typeof json[i].func === 'object') { | |
for (var j = 0; j < json[i].func.length; j++){ | |
if (typeof json[i].func[j] !== 'function'){ | |
throw "Error in supplied JSON at index " + i + ". Expects 'func' to be functions. The " + j + "th entry for 'functions' is not a function"; | |
} | |
$(json[i].selector).bind(json[i].bind_to, json[i].func[j]); | |
} | |
} | |
else { | |
if (typeof json[i].func !== 'function'){ | |
throw "Error in supplied JSON at index " + i + ". Expects 'func' to be a function."; | |
} | |
$(json[i].selector).bind(json[i].bind_to, json[i].func); | |
} | |
} | |
else throw 'Has no functions to bind to!' | |
} | |
} |
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// This class is basically the undo & redo structure of a command pattern - it keeps track of all undo-able commands | |
// Each undo-able command would have an execute() and an unexecute() command. | |
// The user will call this function to undo / redo commands. Note the specific use of garbage collection to avoid a memory leak | |
var history = (function() { | |
var iterator = -1; //marks the "present" command, the last command issued | |
var end = -1; | |
var start = -1; | |
var max_size = 3; | |
var command_history = []; //array to store all the commands | |
return { | |
//TODO if this method isnt fast enough, I can try a linkedlist or an array shift | |
add : function( command ) { | |
if( end >= (max_size - 1) ) { //assuming the client wants max_size in terms of '# of elements' not 'size of base-0 array' | |
command_history[start] = undefined; //we need to let the unused data (the oldest commands) get garbage collected | |
start++, end++; //move the array onwards so we can ignore + safely delete the oldest command in history | |
iterator = end; //move the iterator to the front when a new command is added | |
command_history.push(command); | |
console.log('trying to remove earliest command'); | |
} | |
else { | |
end++; | |
if (start == -1) start = 0; | |
iterator = end; | |
command_history.push(command); | |
} | |
}, | |
undo : function() { | |
if (iterator == (start-1)) return null | |
else { | |
if (iterator == end + 1) iterator = end; | |
if (iterator >= start) { | |
command_history[iterator].unexecute(); | |
iterator--; | |
console.log("iter:" + iterator); | |
} | |
} | |
}, | |
redo : function() { | |
if (iterator == (end+1)) return null | |
else { | |
if (iterator <= end) { | |
iterator++; | |
} | |
if (iterator <= end) { | |
command_history[iterator].execute(); | |
} | |
} | |
}, | |
logger : function() { | |
console.log("start: " + start + " end: " + end); | |
} | |
} | |
})(); |
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// This function makes it easy to keep a div on top of the screen, no matter where the user scrolls | |
var make_sticky = function(selector, location, threshold){ | |
(function(){ // the extra closure is for these variables below | |
var former_position = $(selector).css('position'); | |
var former_top = $(selector).css('top'); | |
$(window).scroll(function () { | |
if($(this).scrollTop() > threshold){ | |
$(selector).css({ | |
"position" : "fixed", | |
"top" : '0px' | |
}); | |
} | |
if ($(this).scrollTop() < threshold){ | |
$(selector).css({ | |
"position" : former_position, | |
"top" : former_top | |
}); | |
} | |
}); | |
})(); | |
} |
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/* | |
Usage: | |
var provided = { | |
arg1 : "arg1", | |
arg1 : 2 | |
} | |
var should_be = { | |
arg1 : "string", | |
arg2 : "object" | |
} | |
This would throw an error for arg2 because it is the wrong type. | |
*/ | |
var Type_checker = function(){ | |
if(this instanceof Type_checker){ | |
var errors = []; | |
this.check = function(check_me, should_be, extra_error_message){ | |
$.each(check_me, function(key, value) { | |
if(typeof value !== should_be[key]){ | |
var should_be_val = should_be[key]; | |
var error = key + ' is a(n) ' + typeof value + ' when it should be a(n) ' + should_be_val; | |
error = error + '. ' + extra_error_message; | |
errors.push(error); | |
} | |
}); | |
return errors; | |
} | |
this.log_errors = function(){ | |
$.each(errors, function(key, value){ | |
console.log(value); | |
}); | |
} | |
} | |
else return new Type_checker() | |
} |
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