承诺执行函数返回未定义

Question

我试图在承诺解决时 return 承诺中的一个值，然后将 returned 值传递给我的状态。但是，无论我尝试什么，我的函数的 return 值都是未定义的。

我的函数是从一个 npm 包导入的，该包在此处有其文档： https://www.npmjs.com/package/synonyms

它意味着 return 给定单词的同义词。

也许我构造 promise 本身的方式存在一些非常明显的问题，导致一些错误的异步计时？

我已经尝试 return 仅调用函数而不将其传递给 resolve 但这会引发错误

searchForSynonymsAndDef = (param) =>{
if(this.state.scholarMode==true){
console.log("INSIDE SYNONYMS")

var synonyms = require("synonyms");

  let p = new Promise((resolve,reject,param)=>{
    var result=resolve(synonyms(param,"n"))

  }).then((result)=>{
    console.log("result is:",result)
  })
  .then((result)=>{
    this.setState({textToReadAloud: "here are some synonyms for "
    +param +"...firstly.....nouns...."+result})
    console.log("here are some synonyms for "+param +"...firstly.....nouns...."+result)
    })
  }else{
    console.log("sorry scholar mode is off")
  }
}

我希望 'result' 是基于传入参数的同义词，但不幸的是结果总是 = undefined :(

Answer 1

searchForSynonymsAndDef = (param) =>{
    if(this.state.scholarMode==true){
    console.log("INSIDE SYNONYMS")

    var synonyms = require("synonyms");
    let p = new Promise((resolve,reject,param)=>{
        resolve(synonyms(param,"n"));
    });
    return p;
}else{
    console.log("sorry scholar mode is off")
}
}

Answer 2

你不需要传递参数来承诺。只需从 Promise 中删除参数即可。

searchForSynonymsAndDef = (param) =>{
if(this.state.scholarMode==true){
console.log("INSIDE SYNONYMS")

var synonyms = require("synonyms");

  let p = new Promise((resolve,reject)=>{
    var result=resolve(synonyms(param,"n"))

  }).then((result)=>{
    console.log("result is:",result)
  })
  .then((result)=>{
    this.setState({textToReadAloud: "here are some synonyms for "
    +param +"...firstly.....nouns...."+result})
    console.log("here are some synonyms for "+param +"...firstly.....nouns...."+result)
    })
  }else{
    console.log("sorry scholar mode is off")
  }
}

承诺执行函数返回未定义

promise executing function returning undefined

javascript

es6-promise

undefined-function