Package Exports

js-dynamic-function

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Readme

DynamicFunction

动态函数，类似于多态函数，但不限于按参数类型条件切换执行体

简介

定义

动态函数是一种特殊的函数，在函数执行前，需要先调用 getExecutor 方法获取函数执行体，如果获得的执行体为非函数，则动态函数将不执行

同时，动态函数拥有一个方法 isExecutable 用以检测动态函数是否可以被执行

声明方式

new DynamicFunction(getExecutor)
// or
new DynamicFunction(name, getExecutor)
// or
new DynamicFunction({ name, getExecutor })

示例

let flag = false

const fn = new DynamicFunction(() => {
  if (!flag) {
    return null
  }

  return (a, b) => a + b
})

fn.isExecutable() // false
fn(1, 2) // nothing happen

flag = true
fn.isExecutable() // true
fn(1, 2) // 3

flag = false
fn.isExecutable() // false
fn(1, 2) // nothing happen

异步

若 getExecutor 函数为异步，则其执行过程及相关方法均为异步

var delay = time => new Promise(resolve => setTimeout(resolve, time))

var fn = new DynamicFunction(async () => {
  await delay(1000)

  return function test(a, b) {
    return a + b
  }
})

await fn(1, 2) // log '3' after 1000 ms
await fn.isExecutable() // log 'true' after 1000 ms
await fn.getName() // log 'test' after 1000 ms
await fn.getLength() // log '2' after 1000 ms

其他

名字

显式声明函数名

var fn = new DynamicFunction('test', () => {...})

// or

var fn = new DynamicFunction({
  name: 'test', 
  getExecutor: () => {...}
})

fn.getName() // test

若未显式声明函数名，则使用 executor 的名称

var fn = new DynamicFunction(() => {
  return function test() {...}
})

fn.getName() // test

参数个数 / 长度

无法显式声明，使用 executor 的长度

var fn = new DynamicFunction(() => {
  return function test(a, b) {...}
})

fn.getLength() // 2