WebAssembly value types

Value types classify the values used in computation.

i32

A 32-bit integer. Interpreted as signed or unsigned per instruction.

i64

A 64-bit integer. Interpreted as signed or unsigned per instruction.

f32

A 32-bit single-precision floating-point value.

f64

A 64-bit double-precision floating-point value.

v128

A 128-bit vector of packed integer or floating-point data, manipulated by SIMD instructions.

funcref

A reference to a function defined in Wasm, allowing higher-order functions to be called across the Wasm and JavaScript language boundaries.

externref

A reference to a host value (for example a JavaScript object), opaque to Wasm code.