jsContext.py

class Obj:
	def __init__(self):
		self.a = 1

	def fn(self, b, c):
		print(self.a,b,c)

a = Obj()
a.fn(2, 3) # (1,2,3)

# Function.prototype.bind()
def bind(function, obj, *args):
	def boundedFunction(*args2):
		finalArgs = list(args + args2)
		return function(obj, *finalArgs)
	return boundedFunction

f = bind(Obj.fn, a, 2)
f(3)  # (1,2,3)
f(4)  # (1,2,4)

f = bind(Obj.fn, a, 2, 3)
f()   # (1,2,3)

f = bind(Obj.fn, a) # this is actually same as a.fn
f(2,3) # (1,2,3)
 
# Function.prototype.call() and Function.prototype.apply()
# Difference is onlyt that this function also perform a function call
# Also, apply takes parameters as array

def call(function, obj, *args):
	return function(obj, *args)

def apply(function, obj, args):  # note - no unpacking with *, apply gets parameters as array already
	return function(obj, *args)

call(Obj.fn, a, 2, 3) # (1,2,3)
apply(Obj.fn, a, [2, 3]) # (1,2,3)