There is pattern for a similar doll cardigan at https://www.ravelry.com/patterns/library/striped-angle-fo...

The cardigan is knitted in two pieces. Each part starts at the sleeve cuff and ends in the middle front, and middle back. It is knitted with double threads and teeteeElegent.
The front part starts with quite few st and ends up with all the stitches you need for the front edge and the bottom edge, all on the same needle. It is therefore a good idea to knit back and forth with a long circular pin.

Approximately yarn use, if you use a yarn with single thread it will be half the length.
Small: 1200m dark grey, 800m light grey, 800m white
Medium: 1300m dark grey, 900m light grey, 900m white
Large: 1450m dark grey, 1000m light grey, 1000m white

Cardigan dimensions in cm for small, medium, large
From sleeve edge to sleeve edge 150, 155, 160
From shoulder to bottom edge 55, 57, 60
Sleeve circumference at hand 19, 20, 21
Sleeve circumference at armpit 38,41,44
Width 104, 110, 118
Neckline between shoulder seams 20, 22, 24
Front edge for buttons 5

You can also use many colors like the two last pictures. This sweater is made from leftovers that have similar yarn weight.