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Ask HN: What is your favorite Javascript code snippet?

6 points by donohoe 16y ago

Any useful gems or ways to overcome common hurdles? Would love to see and compare insights. Preferably framework/library agnostic if possible.

seasoup 16y ago
for (var a=0, len = arr.length; a < len; a++) { // looping for speed, cache the length and save an access }
jashkenas 16y ago
I'm partial to keeping a "bind" function handy. (Function#bind will be in ECMAScript 5, but it's not quite here yet). It's crucial for keeping your sanity when trying to use "this" with callbacks, Ajax, or async. var bind = function(func, context) { var slice = Array.prototype.slice; var args = slice.call(args, 2); return function() { return func.apply(context || {}, args.concat(slice.call(arguments))); }; };
smarterch1ld 16y ago
jQuery
- deleted 16y ago
  [deleted]
keville 16y ago
for (var i=0, node; node=parentElem.childNodes.item(i); i++) { // iterates over an element's child nodes; 2nd statement in for loop returns undefined when out of items }
donohoe 16y ago
Some of these assume you have Firebug or similar for console output. Quick and easy browser sniff: var browser = (function x(){})[-5]=='x' ? 'ff3' : (function x(){})[-6]=='x' ? 'ff2' : /a/[-1]=='a' ? 'ff' : '\v'=='v' ? 'ie' : /a/.__proto__=='//' ? 'safari' : /s/.test(/a/.toString) ? 'chrome' : /^function \(/.test([].sort) ? 'opera' : 'Unknown'; Round to Nearest Multiple var roundThis = 54; var closest = Math.round(parseInt(roundThis)/20)*20; // output = 60 URL Paramaters var parts = window.location.search.substr(1).split("&"); var params = {}; for (var i = 0; i < parts.length; i++) { var temp = parts[i].split("="); params[decodeURIComponent(temp[0])] = decodeURIComponent(temp[1]); } console.log(params); URL Hash Paramaters console.log(window.location.hash.substr(1).split("&"));

6 points by donohoe 16y ago

Any useful gems or ways to overcome common hurdles? Would love to see and compare insights. Preferably framework/library agnostic if possible.

seasoup 16y ago

for (var a=0, len = arr.length; a < len; a++) { // looping for speed, cache the length and save an access }

jashkenas 16y ago

I'm partial to keeping a "bind" function handy. (Function#bind will be in ECMAScript 5, but it's not quite here yet). It's crucial for keeping your sanity when trying to use "this" with callbacks, Ajax, or async. var bind = function(func, context) { var slice = Array.prototype.slice; var args = slice.call(args, 2); return function() { return func.apply(context || {}, args.concat(slice.call(arguments))); }; };

smarterch1ld 16y ago

jQuery

deleted 16y ago
[deleted]

keville 16y ago

for (var i=0, node; node=parentElem.childNodes.item(i); i++) { // iterates over an element's child nodes; 2nd statement in for loop returns undefined when out of items }

donohoe 16y ago

Some of these assume you have Firebug or similar for console output. Quick and easy browser sniff: var browser = (function x(){})[-5]=='x' ? 'ff3' : (function x(){})[-6]=='x' ? 'ff2' : /a/[-1]=='a' ? 'ff' : '\v'=='v' ? 'ie' : /a/.__proto__=='//' ? 'safari' : /s/.test(/a/.toString) ? 'chrome' : /^function \(/.test([].sort) ? 'opera' : 'Unknown'; Round to Nearest Multiple var roundThis = 54; var closest = Math.round(parseInt(roundThis)/20)*20; // output = 60 URL Paramaters var parts = window.location.search.substr(1).split("&"); var params = {}; for (var i = 0; i < parts.length; i++) { var temp = parts[i].split("="); params[decodeURIComponent(temp[0])] = decodeURIComponent(temp[1]); } console.log(params); URL Hash Paramaters console.log(window.location.hash.substr(1).split("&"));