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The safer and faster ECMA5.1 interpreter written by JavaScript, it can be used:

1. Sandbox (like Figma Plugin Sandbox, but better and easier to use);
2. Protect JavaScript source code via AOT compiling to opcode.

sablejs covered ~95% test262 es5-tests cases, it can be safely used in production.

• Quick Start
• APIs
• Benchmark
• Limits
• Bindings
• License

Quick Start

sablejs includes the Compiler and Interpreter independently, so we removed the related dynamic api from the spec (see Limits 1). In short, you need to compile your JavaScript code with sablejs cli before you run it.

Example

Suppose we have the following code in fib.js:

function fib(n) {
  return n < 2 ? n : fib(n - 1) + fib(n - 2);
}

var start = Date.now();
console.log("[INFO] fib: " + fib(30));
console.log("[INFO] time consuming: " + (Date.now() - start) + "ms");

Compile It!

> npm i sablejs -g
> sablejs -i fib.js -o output # get output file that contains base64 string

sablejs cli includes the following commands:

Usage: sablejs [options]

Options:
  -v, --vers           output the current version
  -i, --input <path>   compile input filepath
  -o, --output <path>  compile output filepath
  -j  --json           don't do Base64 compress, output simple json result
  -s, --slient         don't output log
  -h, --help

Run It!

> npm install sablejs --save

or you can import to your html directly

<script src="https://cdn.jsdelivr.net/npm/[email protected]/runtime.js"></script>

Browser

const VM = require("sablejs/runtime")();

// import console.log function to vm call
const vm = new VM();
const vGlobal = vm.getGlobal();
const vConsole = vm.createObject();
const vLog = vm.createFunction("log", function () {
  const temp = [];
  for (let i = 0; i < arguments.length; i++) {
    temp.push(vm.asString(arguments[i]));
  }

  console.log(...temp);
  return vm.createUndefined();
});

vm.setProperty(vConsole, "log", vLog);
vm.setProperty(vGlobal, "console", vConsole);

(async () => {
  const resp = await fetch("<output url>");
  const data = await resp.text();
  vm.run(data);
  vm.destroy();
})();

Node

const VM = require("sablejs/runtime")();
const fs = require("fs");

// import console.log function to vm call
const vm = new VM();
const vGlobal = vm.getGlobal();
const vConsole = vm.createObject();
const vLog = vm.createFunction("log", function () {
  const temp = [];
  for (let i = 0; i < arguments.length; i++) {
    temp.push(vm.asString(arguments[i]));
  }

  console.log(...temp);
  return vm.createUndefined();
});

vm.setProperty(vConsole, "log", vLog);
vm.setProperty(vGlobal, "console", vConsole);

// please run: sablejs -i fib.js -o output
vm.run(fs.readFileSync("./output").toString());
vm.destroy();

APIs

• VM.prototype.run(source, isSimpleJSON)
  • source: String - the compiled result via sablejs compiler
  • isSimpleJSON: Boolean - if be true, you should use -j to make compiler output simple json result, default false.
  • return: undefined

Initialize the VM and execute the compiled source code.

const VM = require('sablejs/runtime')();
const vm = new VM();

// source should be base64 string via sablejs compiling
vm.run(`<compiled source string>`);

• VM.prototype.getGlobal()
  • return: Value

Returns the global in the VM, which is similar to the window in browser and the global in Node.js.

const global = vm.getGlobal();

• VM.prototype.createUndefined()
  • return Value

Create an undefined boxed type.

const vUndefined = vm.createUndefined();

• VM.prototype.createNull()
  • return: Value

Create an null boxed type.

const vNull = vm.createNull();

• VM.prototype.createBoolean(bool)
  • bool: Boolean
  • return Value

Create an bool boxed type.

const vBoolean = vm.createBoolean(true);

• VM.prototype.createNumber(num)
  • num: Number
  • return Value

Create an number boxed type.

const vNumber = vm.createNumber(1024);

• VM.prototype.createString(str)
  • str: String
  • return Value

Create an string boxed type.

const vString = vm.createString('Hello World!');

• VM.prototype.createObject()
  • return Value

Create an object boxed type.

const vObject = vm.createObject();

• VM.prototype.createArray(length)
  • length: Number | undefined
  • return Value

Create an array boxed type.

const vArray1 = vm.createArray();
// or
const vArray2 = vm.createArray(128);

• VM.prototype.createFunction(name, func)
  • name: String
  • func: Function
  • return Value

Create an funcntion boxed type. It receives a function name and the specific implementation of the function. Both the function parameter and this are boxed types in func.

const vFunction = vm.createFunction("trim", function(str) {
  // this is the undefined or new's instannce boxed type
  // str maybe the string boxed type, we need to check it
});

• VM.prototype.createError(message)
  • message: String | undefined
  • return Value

Create an error boxed type.

const vError1 = vm.createError();
// or
const vError2 = vm.createError("unknown error");

• VM.prototype.createRegExp(pattern, flags)
  • pattern: String
  • flags: String | undefined
  • return Value

Create an regexp boxed type.

const vRegExp = vm.createRegExp("\\w+", "ig");

• VM.prototype.createDate()
  • return Value

Create an date boxed type.

const vDate = vm.createDate();

• VM.prototype.isUndefined(value)
  • value: Value
  • return Boolean

Used to determine if the type is undefinend.

const vUndefined = vm.createUndefined();
if(vm.isUndefined(vUndefined)) {
  // ...
}

• VM.prototype.isNull(value)
  • value: Value
  • return Boolean

Used to determine if the type is null.

const vNull = vm.createNull();
if(vm.isNull(vNull)) {
  // ...
}

• VM.prototype.isBoolean(value)
  • value: Value
  • return Boolean

Used to determine if the type is bool.

const vBoolean = vm.createBoolean(true);
if(vm.isBoolean(vBoolean)) {
  // ...
}

• VM.prototype.isNumber(value)
  • value: Value
  • return Boolean

Used to determine if the type is number.

const vNumber = vm.createNumber(1024);
if(vm.isNumber(vNumber)) {
  // ...
}

• VM.prototype.isString(value)
  • value: Value
  • return Boolean

Used to determine if the type is string.

const vString = vm.createString("Hello World!");
if(vm.isString(vString)) {
  // ...
}

• VM.prototype.isObject(value)
  • value: Value
  • return Boolean

Used to determine if the type is object.

const vObject = vm.createObject();
const vArray = vm.createArray();
if(vm.isObject(vObject) && vm.isObject(vArray)) {
  // ...
}

• VM.prototype.isArray(value)
  • value: Value
  • return Boolean

Used to determine if the type is array.

const vArray = vm.createArray();
if(vm.isArray(vArray)) {
  // ...
}

• VM.prototype.isFunction(value)
  • value: Value
  • return Boolean

Used to determine if the type is function.

const vFunction = vm.createFunction("log", function(){});
if(vm.isFunction(vFunction)){
  // ...
}

• VM.prototype.isError(value)
  • value: Value
  • return Boolean

Used to determine if the type is error.

const vError = vm.createError('unknown error');
if(vm.isError(vError)){
  // ...
}

• VM.prototype.isRegExp(value)
  • value: Value
  • return Boolean

Used to determine if the type is regexp.

const vRegExp = vm.createRegExp("\\w+", "ig");
if(vm.isRegExp(vRegExp)){
  // ...
}

• VM.prototype.isDate(value)
  • value: Value
  • return Boolean

Used to determine if the type is date.

const vDate = vm.createDate();
if(vm.isDate(vDate)){
  // ...
}

• VM.prototype.asUndefined(value)
  • value: Value
  • return undefined

Converting undefined boxed type to plain undefined value.

const vUndefined = vm.createUndefined();
vm.asUndefined(vUndefined) === undefined;

• VM.prototype.asNull(value)
  • value: Value
  • return null

Converting null boxed type to plain null value.

const vNull = vm.createNull();
vm.asNull(vNull) === null;

• VM.prototype.asBoolean(value)
  • value: Value
  • return Boolean

Converting bool boxed type to plain bool value.

const vBoolean = vm.createBoolean(true);
const boolean = vm.asBoolean(vBoolean);
if(boolean === true) {
  // ...
}

• VM.prototype.asNumber(value)
  • value: Value
  • return Number

Converting number boxed type to plain number value.

const vNumber = vm.createNumber(1024);
const number = vm.asNumber(vNumber);
if(number === 1024) {
  // ...
}

• VM.prototype.asString(value)
  • value: Value
  • return String

Converting string boxed type to plain string value.

const vString = vm.createString('Hello World!');
const string = vm.asString(vString);
if(string === 'Hello World!') {
  // ...
}

• VM.prototype.asObject(value)
  • value: Value
  • return Object

Converting object boxed type to inner object value.

const vObject = vm.createFunction("asObject", function(){});
const object = vm.asObject(vObject);
if(object.type === 12) {
  // ...
}

• VM.prototype.instanceof(lval, rval)
  • lval: Value
  • rval: Value
  • return Boolean

Equivalent to the instanceof keyword.

const global = vm.getGlobal();
const vDateFunc = vm.getProperty(global, "Date");
const vDate = vm.createDate();
if(vm.instanceof(vDate, vDateFunc)) {
  // ...
}

• VM.prototype.typeof(value)
  • value: Value
  • return String

Equivalent to the typeof keyword.

const vString = vm.createString('Hello World!');
if(vm.typeof(vString) === "string") {
  // ...
}

• VM.prototype.getProperty(value, name)
  • value: Value
  • name: String
  • return Value

Get the value of the property of the object. Return is a property boxed type.

const global = vm.getGlobal();
const vPrint = vm.getProperty(global, "print");
if(vm.isFunction(vPrint)) {
  // ...
}

• VM.prototype.setProperty(value, name, property)
  • value: Value
  • name: String
  • property: Value
  • return Value

Assigning the property to object. Return is a property boxed type.

const global = vm.getGlobal();
const console = vm.createObject();
const log = vm.createFunction("log", function() {
  // console.log impl
});

vm.setProperty(console, "log", log);
vm.setProperty(global, "console", console);

• VM.prototype.deleteProperty(value, name)
  • value: Value
  • name: String
  • return Boolean

Delete the property of object.

const global = vm.getGlobal();
vm.deleteProperty(global, "print");

const vPrint = vm.getProperty(global, "print");
if(vm.isUndefined(vPrint)) {
  // ...
} 

• VM.prototype.defineProperty(value, name, desc)
  • value: Value
  • name: String
  • desc: Object
  • return Value

Equivalent to the Object.defineProperty function.

const vObject = vm.createObject();
vm.defineProperty(vObject, "name", { 
  value: vm.createString("sablejs"),
});

const getter = vm.createFunction("getter", function() {
  return vm.createNumber("101");
});

const setter = vm.createFunction("setter", function(age) {
  vm.setProperty(this, "__age__", age);
});

vm.defineProperty(vObject, "age", {
  enumerable: false,
  get: getter,
  set: setter,
});

• VM.prototype.getPrototype(value)
  • value: Value
  • return Value

Get the prototype of object.

const global = vm.getGlobal();
const vStringFunc = vm.getProperty(global, "String");
if(!vm.isUndefined(vStringFunc)) {
  const vTrimStart = vm.createFunction("trimStart", function() {
    const str = vm.asString(this);
    return vm.createString(str);
  });

  const vStringFuncProto = vm.getPrototype(vStringFunc);
  vm.setProperty(vStringFuncProto, "trimStart", vTrimStart);
}

• VM.prototype.setPrototype(value, prototype)
  • value: Value
  • prototype: Value
  • return Value

Set the prototype of object.

const vA = vm.createFunction("A", function() {});
const vObject = vm.createObject();

vm.setProperty(vObject, 'name', vm.createString('Hello World!'));
vm.setPrototype(vA, vObject);

• VM.prototype.throw(value)
  • value: Value
  • return undefined

Equivalent to the throw keyword.

const vError = vm.createError('unknown error');
vm.throw(vError);

• VM.prototype.new(func[, arg1, arg2, arg3...])
  • func: Value
  • arg: Value
  • return Value

Equivalent to the new keyword.

const vA = vm.createFunction('A', function(name) {
  vm.setProperty(this, 'name', name);
});

vm.new(vA, vm.createString("A"));

• VM.prototype.call(func, thisPtr[, arg1, arg2, arg3...])
  • func: Value
  • thisPtr: Value | undefined
  • arg: Value
  • return Value

Equivalent to the Function.prototype.call function.

const vLog = vm.createFunction('log', function() {
  const temp = [];
  for(let i = 0; i < arguments.length; i++){
    temp.push(vm.asString(arguments[i]));
  }
  console.log(...temp); // '1', 1, false
});

vm.call(
  vLog, 
  vm.createUndefined(), 
  vm.createString('1'), 
  vm.createNumber(1), 
  vm.createBoolean(false)
);

• VM.prototype.destroy
  • return undefined

Destroy the VM instance.

vm.destroy();

Benchmark

sablejs may be the fastest interpreter written in JavaScript (using v8 benchmark suites):

Benchmark Enviorment:

• Node.js v12.19.0
• Golang 1.15.6
• GCC 5.4.0 -O3
• 2.4 GHz Intel Core i9
• MacOS Mojave 10.14.6 (18G6032)

	sablejs	sval	eval5	quickjs-wasm	goja
Language	JavaScript	JavaScript	JavaScript	C + WebAssembly	Golang
Richards	110	24.9	24.7	376	208
Crypto	114	24.6	20.2	400	104
RayTrace	258	92.2	98.5	471	294
NavierStokes	183	35.9	49.8	665	191
DeltaBlue	120	35.3	29.5	402	276
Total score	148	37.3	37.3	452	202
Baseline	1	▼ 2.96	▼ 2.96	▲ 2.05	▲ 0.36
File Size(KB)	216	152	134	434	-
Gzip Size(KB)	29	40	34	245	-

Limits

1. Dynamic execution by eval and Function is forbidden, but passing literal string/number/null and undefined is allowed (the interpreter doesn't contain any compiler).

eval("print('Hello World!')"); // it's ok
eval("var " + "a=1"); // it's ok

var str = "Hello World!";
eval("print('" + str + "')"); // throw SyntaxError

Function("a", "b", "return a+b"); // it's ok
new Function("a", "b", "return a+b"); // it's ok

var str = "return a+b";
Function("a", "b", str); // throw SyntaxError
new Function("a", "b", str); // throw SyntaxError

2. The browser environment relies on native browser functions such as btoa / unescape / decodeURIComponent, etc. if you need support for IE9 or below, you need to add shims.

Bindings

• cax2sablejs - Canvas2D rendering engine for sablejs
• ajax2sablejs - A tiny and simple ajax for sablejs

License

sablejs JavaScript Engine

Copyright (c) 2020-Now ErosZhao

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:

Non-profit projects of individuals or organizations and commercial projects with commercial authorization of the author.

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.