Integers

Integer types

Boa supports the following integer types:

Type	Size (in bytes)	Signed ?	Minimum value	Maximum value
u8	1	No	0	255
u16	2	No	0	65535
u32	4	No	0	4294967295
u64	8	No	0	18446744073709551615
i8	1	Yes	-128	127
i16	2	Yes	-32768	32767
i32	4	Yes	-2147483648	2147483647
i64	8	Yes	-9223372036854775808	9223372036854775807

Integer literals

Integers in Boa can be written in the following bases:

• Base 2, with the 0b prefix
• Base 8, with the 0o prefix
• Base 16, with the 0x prefix.

let base_2 = 0b10000000
let base_8 = 0o200
let base_16 = 0x80

Integer literals can contain ', to make them more legible:

let one_billion = 1'000'000'000

Integer literals and type inference

When creating a variable storing an integer without any type annotation, Boa will, in the following order:

• Assume it is a i32 if the value fits inside a i32
• Assume it is a i64 if the value fits inside a i64
• Assume it is a u64 if the value fits inside a u64
• Raise a compilation error.

The following example illustrates this behavior:

let a = 12 // 12 fits into an i32, so a is an i32
let b = 2147483648 // b is too big for an i32 but fits in an i64 so it is an i64
let c = 9223372036854775808 // c is too big for an i64 but fits in an u64 so it is an u64
let d = 18446744073709551616 // d is too big for an u64 so a compilation error is raised

If the type of the variable is specified and the value does not fit inside it, a compilation error is directly raised:

let a: u8 = 256 // compilation error because 256 is too big to fit in an u8