JavaScript binding, function apply, function call

December 28, 2012

In JavaScript, binding is always explicit, and can be easily lost, so a method using “this” will not refer to the proper object in all situations, ¬†unless you force it to.

JavaScript provides two options to do explicit binding “apply” and “call”.

Apply

Every JavaScript function is equipped with “apply” method that allows you to call the function with specific binding. I takes two arguments, the binding object and an array of arguments to be passed to the function.

fun.apply(thisArg[, argsArray])

Call

“Call” method is similar to “apply”, but it takes the arguments themselves not an array.

fun.call(thisArg[, arg1[, arg2[, ...]]])

References

http://www.alistapart.com/articles/getoutbindingsituations

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/apply

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/call

http://stackoverflow.com/questions/962033/what-underlies-this-javascript-idiom-var-self-this

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