end is used to end a block, loop, if, or else. In the other examples we used the s-expression syntax which doesn’t require the end, so you won’t find it in the other examples here. However, it’s still useful to know about since this is what the browsers display in devtools.

(module
  ;; import the browser console object, you'll need to pass this in from JavaScript
  (import "console" "log" (func $log (param i32)))

  (func
    i32.const 0 ;; change to positive number if you want to run the if block
    if
      i32.const 1
      call $log ;; should log '1'
    end
  )

  (start 1) ;; run the first function automatically
)

const url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(fetch(url), { console });

Syntax

i32.const 0
if
  ;; do something
end

InstructionBinary opcodeend0x0b

Specifications

Browser compatibility