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https://github.com/bplok20010/eval5

A JavaScript interpreter written in TypeScript - Support ES5
https://github.com/bplok20010/eval5

eval5 interpreter javascript-interpreter js-interpreter sandbox typescript-javascript vm wechat-mini

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A JavaScript interpreter written in TypeScript - Support ES5

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README

        

# eval5

[中文](./README.md) | English

[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/bplok20010/eval5/blob/master/LICENSE)
[![npm](https://img.shields.io/npm/v/eval5)](https://www.npmjs.com/package/eval5)
[![npm bundle size](https://img.shields.io/bundlephobia/min/eval5)](https://raw.githubusercontent.com/bplok20010/eval5/master/umd/eval5.min.js)

A JavaScript interpreter written in TypeScript, Supports full ES5 syntax.

> Support JavaScript running environment such as browser, node.js, WeChat Mini Program, etc

[Try it out](https://bplok20010.github.io/eval5/)

[Examples](https://bplok20010.github.io/eval5/examples.html)

## You may not need it unless

- Need to execute code in the browser with a sandbox environment
- Controlling execution time
- JavaScript runtime environment that does not support `eval` and `Function`. for example: WeChat Mini Program [demo](https://github.com/bplok20010/eval5-wx-demo)
- Be interested or Be curious

## ECMAScript version supported

ES5

## Install

```
npm install --save eval5
```

## Usage

[![Edit eval5](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/eval5-zxndl?fontsize=14&hidenavigation=1&theme=dark)

```javascript
import { Interpreter } from "eval5";

const interpreter = new Interpreter(window, {
timeout: 1000,
});

let result;

try {
result = interpreter.evaluate("1+1");
console.log(result);

interpreter.evaluate("var a=100");
interpreter.evaluate("var b=200");
result = interpreter.evaluate("a+b");

console.log(result);
} catch (e) {
console.log(e);
}
```

## Options

```ts
interface Options {
// default: 0 not limited
timeout?: number;
// readonly
rootContext?: {} | null;
globalContextInFunction?: any;
}
```

Example

```
import { Interpreter } from "eval5";

const ctx = {};
const interpreter = new Interpreter(ctx, {
rootContext: window,
timeout: 1000,
});

interpreter.evaluate(`
a = 100;
console.log(a); // 100
`);

window.a;//undefined

```

## Interpreter

**`version`**

current version

**`global`**

default: `{}`

global context

```js
Interpreter.global = window;
const interpreter = new Interpreter();
interpreter.evaluate('alert("hello eval5")');
```

**`globalContextInFunction`**

default: `undefined`

`eval5` does not support `use strict` mode, but the default value of `this` in function calls is `undefined`, you can set this property as the default.

```js
import { Interpreter } from "Interpreter";

const ctx = {};
const interpreter = new Interpreter(ctx);
interpreter.evaluate(`
this; // ctx
function func(){
return this; // undefined
}
func();
`);
```

```js
import { Interpreter } from "Interpreter";

Interpreter.globalContextInFunction = window;
const ctx = {};
const interpreter = new Interpreter(ctx);
interpreter.evaluate(`
this; // ctx
function func(){
return this; // window
}
func();
`);
```

Let's take a look at the following example

> **Note: Illegal invocation**
>
> that's why `globalContextInFunction` is set to `undefined`

```
import { Interpreter } from "Interpreter";

Interpreter.globalContextInFunction = {};

const ctx = {alert: alert};

const interpreter = new Interpreter(ctx);

interpreter.evaluate(`
// alert.call({}, 'Hello eval5')
// Illegal invocation
alert('Hello eval5');
`);
```

**`constructor(context = Interpreter.global, options?: Options )`**

---

## Instance methods

**`evaluate(code: string): any`**

executes string code and returns the value of the last expression

```js
import { Interpreter } from "Interpreter";

const interpreter = new Interpreter(window);

const result = interpreter.evaluate(`
var a = 100;
var b = 200;

a+b;

`);

console.log(result); // 300
```

**`appendCode(code: string): any`**

alias of `evaluate`

**`getExecutionTime(): number`**

get the last execution time

**`setExecTimeout(timeout: number = 0): void`**

set the timeout for each execution

**`getOptions(): Readonly`**

get interpreter options

## evaluate(code: string, ctx?: {}, options?: Options)

executes string code and returns the value of the last expression

> note: a new interpreter is created with every execution

```js
import { evaluate } from "eval5";

evaluate(
`
var a = 100;
var b = 100;
console.log(a+b);
`,
{ console: console }
); // 200

evaluate(`
a;
`); // a is not defined
```

## Function

use `Interpreter.global` as the default context, `Interpreter.globalContextInFunction` also

```js
import { Function } from "eval5";

const func = new Function("a", "b", "return a+b;");
console.log(func(100, 200)); // 300
```

## vm

see [vm](https://nodejs.org/dist/latest-v13.x/docs/api/vm.html)

- vm.createContext
- vm.compileFunction
- vm.runInContext
- vm.runInNewContext
- vm.Script

## License

MIT

## Related

- [evaljs](https://github.com/marten-de-vries/evaljs)
- [closure-interpreter](https://github.com/int3/closure-interpreter)