Binding applies to a variable

Question

Does anyone know why in javascript this works

m = Math.max
m.apply(null, [1,2,3])

but is it not so?

m = Math.max.apply
m(null, [1,2,3])

It throws an exception:

TypeError: Function.prototype.apply was called on undefined, which is undefined, not a function

Answer 1

According to spec

• If IsCallable (func) is false, throw a TypeError exception.

funcis the object on which the method is invoked apply.

applyallows you to specify the context functionlater, which undefinedin your case, since the Function (which should be specified in the arguments) mhas no context .

Since the arguments

TypeError: Function.prototype.apply undefined, undefined,

,

1:

m = Math.max.apply.bind(this)
m(this, [1,2,3]) 

TypeError: Function.prototype.apply , ,

2:

m = Math.max.apply.bind(null)
m(this, [1,2,3])

TypeError: Function.prototype.apply null, ,

3: ( , )

m = Math.max.apply.bind(function(){})
m(this, [1,2,3])

undefined

4: (, )

m = Math.max.apply.bind(Math.max)
m(this, [1,2,3])

3

Answer 2

, , Javascript. Javascript , , . , , , this .

apply - , , , Math.max. apply . m apply, , , apply , .