jquery - Simulate C# Lambda methods in Javascript -


i simulate c# any() method, can used determine whether if collection has matching objects based on lambda expression.

i used jquery's $.grep make things easier:

array.prototype.any = function (expr) {      if (typeof jquery === 'undefined')         throw new referenceerror('jquery not loaded');      return $.grep(this, function (x, i) {         return eval(expr);     }).length > 0;  };  var foo = [{ a: 1, b: 2 }, { a:1, b: 3 }];  console.log(foo.any('x.a === 1')); //true console.log(foo.any('x.a === 2')); //false

i know eval() bad practice obvious reasons. ok in case, since won't use related user inputs?

can done without eval()? can't figure out way pass expression function without evaluating it.

http://jsfiddle.net/dggvn/

i suggest take @ js closures. in particular, did there can done natively in js using array.some method:

[{ a: 1, b: 2 }, { a:1, b: 3 }].some(function(x) { return x.a === 1; }); // true [{ a: 1, b: 2 }, { a:1, b: 3 }].some(function(x) { return x.a === 2; }); // false

edit: in case we're not using closures rather plain simple anonymous functions...


Comments

Post a Comment

Popular posts from this blog

jquery - How can I dynamically add a browser tab? -

since using iframes house external pages are, accounts "not preferred method" , disallowed sites (flickr, one), want dynamically generate browser tabs. e.g., when user submits form, want dynamically generate tab on browser in response submitted. e.g., might want add new tab url like: http://www.bigsurgarrapata.com/contact how in jquery? you want form target attribute action attribute. http://www.w3schools.com/tags/att_form_target.asp browsers have ultimate control on result of target attribute open new tab value of _blank. <form action="contact_submit.php" target="_blank" method="post">
Read more

node.js - Getting the socket id,user id pair of a logged in user(s) -

i have web application done using node js , in it,i have authentication system requires users log in before can access pages. have 2 pages,the homepage , updates page. from read docs,a new socket id issued when user opens tab in browser. me being admin,i know socket id of logged in user , more so,the socket id,logged in user id pair logged in users. what method can use socket id,logged in user id pair make sure broadcast realtime info users online?.
Read more

keyboard - C++ GetAsyncKeyState alternative -

i using windows.h library's getasynckeystate function define key pushed on keyboard . here program returns int value of pushed key example. #include <iostream> #include <windows.h> using namespace std; int main (){ char i; for(i=8;i<190;i++){ if(getasynckeystate(i)== -32767){ cout<<int (i)<<endl; } } return 0; } but trying make opengl simple game , function appeared slow . there function not need cycle 180 times , if statement . thanks you're trying make opengl game, you're going use glfw. if that's case can away using glfwgetkey() such: if (glfwgetkey(glfw_key_up) == glfw_press) {...} if (glfwgetkey(glfw_key_down) == glfw_press) {...} that method nicely explained in tutorial 6 opengl-tutorial.org . should start first tutorial of beginners tutorials , later intermediate tutorials . if you're going make win32 window can listen wm_keydown or wm_keyup messages , virtua
Read more