/**
* 產生Promise物件，具備鏈式resolve與reject
* 主要受jQuery Deferred概念啟發
*
* Unit Test: {@link https://github.com/yuda-lyu/wsemi/blob/master/test/genPm.test.mjs Github}
* @memberOf wsemi
* @returns {Object} 回傳Promise物件
* @example
*
* async function topAsync() {
*
* function test1() {
* return new Promise((resolve, reject) => {
* let ms = []
*
* let fn = function(name) {
* let pm = genPm()
* setTimeout(function() {
* ms.push('resolve: ' + name)
* pm.resolve('resolve: ' + name)
* }, 1)
* return pm
* }
*
* fn('abc')
* .then(function(msg) {
* console.log('t1 then', msg)
* ms.push('t1 then: ' + msg)
* })
* .catch(function(msg) {
* console.log('t1 catch', msg)
* ms.push('t1 catch: ' + msg)
* })
* .finally(() => {
* resolve(ms)
* })
*
* })
* }
* console.log('test1')
* let r1 = await test1()
* console.log(JSON.stringify(r1))
* // test1
* // t1 then resolve: abc
* // ["resolve: abc","t1 then: resolve: abc"]
*
* function test2() {
* return new Promise((resolve, reject) => {
* let ms = []
*
* let fn = function(name) {
* let pm = genPm()
* setTimeout(function() {
* ms.push('reject: ' + name)
* pm.reject('reject: ' + name)
* }, 1)
* return pm
* }
*
* fn('abc')
* .then(function(msg) {
* console.log('t1 then', msg)
* ms.push('t1 then: ' + msg)
* })
* .catch(function(msg) {
* console.log('t1 catch', msg)
* ms.push('t1 catch: ' + msg)
* })
* .finally(() => {
* resolve(ms)
* })
*
* })
* }
* console.log('test2')
* let r2 = await test2()
* console.log(JSON.stringify(r2))
* // test2
* // t1 catch reject: abc
* // ["reject: abc","t1 catch: reject: abc"]
*
* }
* topAsync().catch(() => {})
*
*/
function genPm() {
let resolve
let reject
let p = new Promise(function() {
resolve = arguments[0]
reject = arguments[1]
})
p.resolve = resolve
p.reject = reject
return p
}
export default genPm