WebAssembly.table.length

The length protoype property of the Table object returns the length of the table, i.e. the number of references stored in the table.

Syntax

var tableLength = table.length;

Value

A number.

Examples

The following example (see table.html on GitHub, and view it live also) compiles and instantiates the loaded table.wasm byte code using the WebAssembly.instantiate() method. It then exports a table from the module and retrieves the references stored in it.

fetch('table.wasm').then(function(response) {
  response.arrayBuffer().then(function(bytes) {
    WebAssembly.instantiate(bytes).then(function(obj) {
      var tbl = obj.instance.exports.tbl;
      console.log(tbl.get(0)());  // 13
      console.log(tbl.get(1)());  // 42

      console.log(tbl.length);
    });
  });
});

Note how you've got to include a second function invocation operator at the end of the accessor to actually retrieve the value stored inside the reference (e.g. get(0)() rather than get(0)) — it is a function rather than a simple value.

At the end of the inner block we log the length of the table instance to the console.

Specifications

Specification	Status	Comment
Web Assembly JavaScript API The definition of 'length' in that specification.	Draft	Initial draft definition.

Browser compatibility

[1] Experimental support can be enabled in Chrome 51+ and Opera 38+ by going to chrome://flags and enabling the Experimental WebAssembly flag.

[2] Experimental support can be enabled in Firefox 47+ by enabling the javascript.options.wasm flag in about:config.

See also

• WebAssembly landing page.
• WebAssembly concepts
• Using the WebAssembly JavaScript API