The UN partition plan for Mandatory Palestine most emphatically did not include the West Bank.
The original Israeli portions consisted of three sections; a northern, roughly triangular enclave running from Lake Huleh south around Lake Tiberias (also called Lake Kinneret or the Sea of Galilee) along the Jordan to a point approximately where the border with Jordan lies today, then roughly northwest as far Nazareth.
The next section comprised the coastal plain stretching from Haifa in the north to a point south of Tel-Aviv-Jaffa approximately parallel with Jerusalem.
The last and largest portion was comprised mostly of the Negev Desert and was connected to the coastal plain by a narrow corridor. The southern section was smaller than it is today though it did include Eilat, it did not include Beersheeba. Gaza and the El Ajua area were also much enlarged.
The proposed state was largely indefensible, the Arabs rejected the plan and went to war. The Jewish Agency voted to accept the partition plan, defended themselves successfully and did a bit of justifiable “ethnic cleansing”, driving Arab populations out of the areas they took during the course of operations in the ‘48 War (Operation Iron Broom).
IMHO they should have pursued a similar policy after ‘67 and secured a patrimony for themselves and their posterity along with defensible borders.