Big Ints 18

Question 1

Why were bigints added in ECMAScript2020?

Answer 1

Before, js could only suppost ~53 bits. Anything larger would have to be stored in a string.

Bigints are used widely in fin tech. They multiply (internally) by 100 to get rid of the cents.

Question 2

What are big ints?

Answer 2

New primitive data type for Numbers without a fixed storage size, they adapt to the integers they represent.

Question 3

Which bases do bigint literals support?

Answer 3

Decimal: 123n
Hexadecimal: 0xFFn
Binary: 0b1101n
Octal: 0o777n

Question 4

With most operators, we are not allowed to mix bigints and numbers. If we do exceptions are thrown. How come?

Answer 4

Bc there is no general way of coercing a number and a bigint to a common type. Numbers can’t represent bigints beyond 53 bits and bigints can’t represent fractions.

However, you can compare bigints and numbers

Question 5

Can you serialize a bigint? hint: JSON.stringify(1n)

Answer 5

No

Question 6

How does one decide to use numbers vs bigints?

Answer 6

Use numbers for up to 53 bits and for Array indices. Rationale: they already appear everywhere and are handled efficiently by most engines (especially if they fit into 32 bits)