Math.min.apply(0, array) - why?

Question

I was just digging through some JavaScript code (Raphaël.js) and came across the following line (translated slightly):

Math.min.apply(0, x)

Answer 1

The reason is this:

• Your input x is an array

• The signature of Math.min() doesn't take arrays, only comma separated arguments

• If you were using Function.prototype.call() it would have almost the same signature, except the first argument is the this context, i.e. who's "calling"

  • Example: Math.min.call(context, num1, num2, num3)

• The context only matters when you refer to this inside the function, e.g. most methods you can call on an array: Array.prototype. would refer to this (the array to the left of the 'dot') inside the method.

• Function.prototype.apply() is very similar to .call(), only that instead of taking comma-separated arguments, it now takes an array after the context.

  • Function.prototype.call(context, arg1, arg2, arg3)
  • Function.prototype.apply(context, [arg1, arg2, arg3])

• The 0 or null that you put in as the first argument is just a place shifter.