编辑代码

// proove js evaluate args from left to right
x = 3
function mut()
{
    x = x * 2
    return x
}
function test(x, y)
{
    console.log('x=', x, ' y=', y)
    return x + y
}
test(x, mut())  // --> x = 3, y = 6
test(mut(), x)  // --> x = 6, y = 6