WebAssembly.Table.prototype.set()
The set()
prototype method of
the WebAssembly.Table
object mutates a reference stored at a given index
to a different value.
Syntax
js
set(index, value)
Parameters
index
-
The index of the function reference you want to mutate.
value
-
The value you want to mutate the reference to. This must be an exported WebAssembly function, a JavaScript wrapper for an underlying Wasm function.
Return value
None (undefined
).
Exceptions
-
If index is greater than or equal
to
Table.prototype.length
, aRangeError
is thrown. -
If value is not an exported WebAssembly function or
null
, aTypeError
is thrown.
Examples
Using Table.set
The following example (see table2.html source code
and live version)
creates a new WebAssembly Table instance with an initial size of 2
references. We then print out the table length and contents of the two indexes
(retrieved via Table.prototype.get()
) to show that
the length is two, and the indexes currently contain no function references (they
currently return null
).
js
const tbl = new WebAssembly.Table({ initial: 2, element: "anyfunc" });
console.log(tbl.length);
console.log(tbl.get(0));
console.log(tbl.get(1));
We then create an import object that contains a reference to the table:
js
const importObj = {
js: { tbl },
};
Finally, we load and instantiate a Wasm module (table2.wasm) using the
WebAssembly.instantiateStreaming()
, log the table length, and invoke the
two referenced functions that are now stored in the table (the table2.wasm module (see
text representation)
adds two function references to the table, both of which print out
a simple value):
js
WebAssembly.instantiateStreaming(fetch("table2.wasm"), importObject).then(
(obj) => {
console.log(tbl.length);
console.log(tbl.get(0)());
console.log(tbl.get(1)());
}
);
Note how you've got to include a second function invocation operator at the end of the
accessor to actually invoke the referenced function and log the value stored inside it
(e.g. get(0)()
rather than get(0)
) .
This example shows that we're creating and accessing the table from JavaScript, but the same table is visible and callable inside the Wasm instance too.
Specifications
Specification |
---|
WebAssembly JavaScript Interface # dom-table-set |
Browser compatibility
BCD tables only load in the browser