I need the code "in detail" for ODE solution in JavaScript ( ECMASCRIPT program )

Consider a first order ordinary differential equation given by:

y ' = f (x,y) = y*x^2 -1.2y

with a starting value of y (0) = 1 on the interval x = 0 to 2 with n = 8 (step size will be h = 0.25 )

determine the value of y (2) using:

(a) Euler's method

on each interval the next y value = previous y value + slope times step size.

or yn = y + f(x,y) * h

(b) Heun's method

k1 = f ( x, y )

k2 = f ( x+h, y+k1*h )

and

yn = y + (k1 + k2) * h / 2

(c) RK-3 method

k1 = f ( x, y )

k2 = f ( x+h/2, y+k1*h/2 )

k3 = f ( x+h, y -k1*h + 2*k2*h)

and

yn = y + (k1 + 4*k2 + k3) * h/6

(d) RK-4 method

k1 = f ( x, y )

k2 = f ( x+h/2, y+k1*h/2 )

k3 = f ( x+h/2, y+k2*h/2 )

k4 = f ( x+h, y + k3*h)

and

yn = y + (k1 + 2*k2 + 2*k3 + k4) * h / 6

at the start of the program I need you to define:

function f (x,y)

initial values: x = 0 and y = 1

final value: b = 2

number of steps: n = 8

you will need to display the four ending values for y:

(a) Euler's method

(b) Heun's method

(c) RK-3 method

(d) RK-4 method