使用回调“未定义不是函数”

Question

I'm creating a twitter bot that is requesting from the same API, Wordnik, but each request is depending on the last request's results. So, I decided to try creating some code using callbacks to make sure that all of the information is returned from the API before the next function runs. I am having trouble setting it up, I have looked at many examples and I just cannot get the hang of it. (Sorry for the messy code).

The error I am getting right now is "undefined is not a function" in my function getWord() on thenRunThisFunction(getRhyme). I'm wondering if I have a small error with the callbacks or if my whole approach to this problem is incorrect?

function runBot() {
var request = require('request');
var Twit = require('twit');
var async = require('async');
var T = new Twit({
    consumer_key:         '' // Your Consumer Key
  , consumer_secret:      '' // Your Consumer Secret
  , access_token:         '' // Your Access Token
  , access_token_secret:  '' // Your Access Token Secret
});

var WORDNIKAPIKEY = '';

// GLOBAL VARS
var randomWord; //get random word
var rhymingWord; //get rhyming word
var bogusDef; //get def of rhyming word
var tweet; // combined random and bogusdef 

function getWord(thenRunThisFunction){ 
    request('http://api.wordnik.com:80/v4/words.json/randomWord?hasDictionaryDef=false&minCorpusCount=0&maxCorpusCount=-1&minDictionaryCount=1&maxDictionaryCount=-1&minLength=5&maxLength=-1&api_key=' + WORDNIKAPIKEY, function (error, response, body1) {
        if (!error && response.statusCode == 200) {
        //console.log(body1) // Show the HTML for the Google homepage. 
        var pparsedData = JSON.parse(body1);
        console.log("Word: " + pparsedData.word);

        // set random word
        randomWord = pparsedData.word;
        thenRunThisFunction(getRhyme);
        }
    })
}

// Get the rhyming word
function getRhyme(thenRunThisFunction){
    request('http://api.wordnik.com:80/v4/word.json/' + randomWord + '/relatedWords?useCanonical=false&relationshipTypes=rhyme&limitPerRelationshipType=10&api_key=' + WORDNIKAPIKEY, function (error, response, body2) {
        if (!error && response.statusCode == 200) {
        //console.log(body2) // Show the HTML for the Google homepage. 
        var o = JSON.parse(body2);
        console.log("Rhyme: " + o[0].words[0]);

        // set rhyming word
        rhymingWord = o[0].words[0];
        thenRunThisFunction(getDef);
        }
    })
}

// GET THE SEXY DEFINITION BABY, BEACH BOD
function getDef(thenRunThisFunction){       
    request('http://api.wordnik.com:80/v4/word.json/' + rhymingWord + '/definitions?limit=200&includeRelated=true&sourceDictionaries=all&useCanonical=false&includeTags=false&api_key=' + WORDNIKAPIKEY, function (error, response, body3) {
        if (!error && response.statusCode == 200) {
        //console.log(body3) // Show the HTML for the Google homepage. 
        var newnew = JSON.parse(body3);
        console.log("Definition: " + newnew[0].text);

        // set definition 
        bogusDef = newnew[0].text;

        randomWord = randomWord.charAt(0).toUpperCase();
        tweet = randomWord + ": " + bogusDef;
        thenRunThisFunction(postStatus);
        }
    })
}   

function postStatus(){
    T.post('statuses/update', { status: tweet }, function(err, data, response) {
        if(err) {
            console.log("There was a problem tweeting the message.", err);
        }
    });
    console.log("status posted");
}
getWord();
}
runBot();

Answer 1

您没有将函数引用传递给getWord（）。

Answer 2

I have no clue really what you're trying to accomplish, instead of going

thenRunThisFunction();
thenRunThisFunction();
thenRunThisFunction();
thenRunThisFunction();
thenRunThisFunction();

Just invoke them by their names, remove the argument from them

getRhyme();
getDef();

What you're doing will never work, you're trying to call thenRunThisFunction as if it actually exists, it's an argument in your function that never gets served

Your method would work if it was like this:

function runThisFunction(fnc) {
  fnc();   
}

function blah(thenRunThisFunction) {
    thenRunThisFunction(thing);
}

function thing() {
  console.log('Blah');
}

blah(runThisFunction);

But that's horrible and bad.

Answer 3

You aren't passing anything to getWord at the end so thenRunThisFunction is literally undefined. Try passing a function to getWord like this getWord(function(){}). But in your case you want to pass whatever you want to run after get word.