This project is a wrapper around the Duktape Embedded Javascript Engine compiled to webassembly/asmjs.
while(true) {} lock up).DuktapeVM().then((vm) => {
vm.eval("2 + 2") // returns "4";
vm.eval("var testObj = {foo: 'bar'};");
vm.eval("testObj.foo") // returns "bar";
vm.evalAsync(`
setTimeout(function() {
_success("hello, world!");
}, 1000);`,
).then((res) => {
console.log(res) // hello, world!
})
});
npm i duktape-vm --save
Using in Typescript/Babel project:
import { DuktapeVM } from "duktape-vm";
Using in Node:
const DuktapeVM = require("duktape-vm").DuktapeVM;
To use directly in the browser, drop ONE of the tags below into your <head>.
The library will attach DuktapeVM to window/global, allowing you to access it anywhere in your code.
<!-- Webassembly Only Version (Fast with 75% browser support), 110KB -->
<script src="https://cdn.jsdelivr.net/npm/duktape-vm@0.1.4/build/duktape-vm.min.js"></script>
<!-- AsmJS Only Version (Slower with 95% browser support), 115KB -->
<script src="https://cdn.jsdelivr.net/npm/duktape-vm@0.1.4/build/duktape-vm.min.asm.js"></script>
<!-- Webassembly with AsmJS fallback (Fast with 95% browser support), 220KB -->
<script src="https://cdn.jsdelivr.net/npm/duktape-vm@0.1.4/build/duktape-vm.min.both.js"></script>
The vm doesn't expose any platform specific methods like window, document, global, fetch or anything like that. Only a subset of APIs are available: setInterval, setTimeout, clearTimeout, clearInterval, Date, Array, String, Number, Object, RegExp, JSON, parseInt, isNaN and Promise.
Additional methods and variables can be provided by passing them into the DuktapeVM constructor.
DuktapeVM(`
// Provide data and methods to VM instance
// vm_breakout() allows you to eval code in the parent window/global space.
// vm_breakout is only available here, it's not available in subsequent "vm.eval" or "vm.evalAsync" calls.
// all methods should be attached to the exports object
exports.console = function(message) {
// print to parent console
vm_breakout("console.log('" + message + "');")
};
// you can also inline js libraries here
// global scope is available on the variable "self"
`).then((vm) => {
// vm contains the javascript vm reference
// Standard eval
let value = vm.eval("2 + 2"); // value contains "4";
// Eval with arguments
// arguments are passed as array called "args"
// when you use arguments you muse use "return" if you want to get the value back.
vm.eval(`return args[0] + args[1]`, [2, 3]); // returns 5
// Messaging API
vm.eval(`
exports.onMessage(function(msg) {
// got message from parent!
})
// send message to parent
exports.message("some message to parent");
`);
// Send message to vm
vm.message("this is a message to the vm");
// Listen for messages from vm
vm.onMessage((msg) => {
console.log("Got message from vm: " + msg);
});
// Async eval
// use _success and _error as callbacks
vm.evalAsync(`
setTimeout(function() {
_success("done!");
// _error("something went wrong!");
}, 1000);
`).then((result) => {
console.log(result) // "done"
});
// Async Eval with arguments
// arguments are passed in as "args" array
vm.evalAsync(`
setTimeout(function() {
_success(args[0]);
// _error("something went wrong!");
}, 1000);
`, ["hello world!"]).then((result) => {
console.log(result) // "hello world!"
});
// reload vm
// dumps the stack, makes a new one, then runs the init code again
vm.reset();
// destroy vm
vm.destroy();
})
Copyright (c) 2018 Scott Lott
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
FAQs
Javascript VM running in WebAssembly
We found that duktape-vm demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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