About
quick.js based sandbox
npm install define-function
works in any WebAssembly environment
- node
- browser
- wechat miniprogram
Usage
define a function dynamically with javascript source code
const def = require('define-function')
const f = await def(`
return 'hello';
`)
f() // 'hello'
function can have argument
const def = require('define-function')
const f = await def(`
const [hello, world] = arguments;
return hello + ' ' + world;
`)
f('hello', 'world') // 'hello world'
argument can be function
const def = require('define-function')
const f = await def(`
const [print] = arguments;
print('hello')
`)
f((msg) => {
console.log(msg)
}) // 'hello'
argument can be async function
const def = require('define-function')
const f = await def(`
const [print, sleep] = arguments;
(async() => {
print('hello')
await sleep(1000);
print('world')
})();
`)
f(
msg => console.log(msg),
milliseconds => new Promise(resolve => setTimeout(resolve, milliseconds))
)
// hello
// world
can return promise back to host
const def = require('define-function')
const f = await def(`
const [print, sleep] = arguments;
return (async() => {
print('hello')
await sleep(1000);
print('world')
})();
`)
await f(
msg => console.log(msg),
milliseconds => new Promise(resolve => setTimeout(resolve, milliseconds))
)
console.log('done')
// hello
// world
// done
share context between multiple invocations
const { context } = require('define-function')
const ctx = context()
const f = await ctx.def(`
global.counter = (global.counter || 0)+1;
return counter; // counter can be referenced globally
`)
f() // 1
f() // 2
f() // 3
ctx.dispose()
inject value and callbacks into global
const { context } = require('define-function')
const ctx = context({ global: {
console,
anwerOfEverything() {
return 42;
}
} }) // inject console and anwerOfEverything to global
const f = await ctx.def(`
console.log(anwerOfEverything());
`)
f() // 42
ctx.dispose();
import and export es module
const { context } = require('define-function')
const ctx = context({
loadModuleContent(moduleName) {
if (moduleName !== 'xxx') {
throw new Error('expect xxx');
}
return `export function sayHello() { return 'hello' }`
}
});
const { hello } = await ctx.load(`
import { sayHello } from 'xxx';
export const hello = sayHello();
`)
console.log(hello) // hello
ctx.dispose();
Limit
- function argument does not support Set/Map/Class or anything that can not survive JSON.parse(JSON.stringify), except the argument is a function
- function return value does not support Set/Map/Class or anything that can not survive JSON.parse(JSON.stringify), except promise object
- JSON.stringify and JSON.parse takes time, so the arguments and return value should be as small as possible for best performance
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