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What would you like to do?
Simple type checking in JavaScript.
(function (root) {
var type = function (o) {
// handle null in old IE
if (o === null) {
return 'null';
}
// handle DOM elements
if (o && (o.nodeType === 1 || o.nodeType === 9)) {
return 'element';
}
var s = Object.prototype.toString.call(o);
var type = s.match(/\[object (.*?)\]/)[1].toLowerCase();
// handle NaN and Infinity
if (type === 'number') {
if (isNaN(o)) {
return 'nan';
}
if (!isFinite(o)) {
return 'infinity';
}
}
return type;
};
var types = [
'Null',
'Undefined',
'Object',
'Array',
'String',
'Number',
'Boolean',
'Function',
'RegExp',
'Element',
'NaN',
'Infinite'
];
var generateMethod = function (t) {
type['is' + t] = function (o) {
return type(o) === t.toLowerCase();
};
};
for (var i = 0; i < types.length; i++) {
generateMethod(types[i]);
}
if (typeof exports === "object" && exports) {
exports = type;
}
else if (typeof define === "function" && define.amd) {
define(type);
}
else {
root.type = type;
}
})(this);
@Starefossen

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Starefossen Nov 6, 2013

Nicely done!

Starefossen commented Nov 6, 2013

Nicely done!

@L8D

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L8D Nov 6, 2013

Checkout http://jsperf.com/type-cecking for some performance comparisons…

L8D commented Nov 6, 2013

Checkout http://jsperf.com/type-cecking for some performance comparisons…

@PhilJ

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PhilJ Nov 29, 2013

Jon, I listend to you awesome talk at JSConf.eu 2013 and have been using the type() method you proposed in your presentation in some of my hobby projects since then (most usually to assert parameter values).

I'd love to see this as an npm plugin, that i don't need to copy it in every project! ;)

PhilJ commented Nov 29, 2013

Jon, I listend to you awesome talk at JSConf.eu 2013 and have been using the type() method you proposed in your presentation in some of my hobby projects since then (most usually to assert parameter values).

I'd love to see this as an npm plugin, that i don't need to copy it in every project! ;)

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