azure异步javascript后端-等待函数
我正在使用Azure移动服务和javascript后端。我的问题是该函数不等待其他函数的结束 我试着选择一个有分词规则的词。我想选择item.wordnumber最高的项目。如果没有几个项目具有相同的item.wordnumber,我想在其他表中选择与该项目关联的投票数最高的人 此脚本不等待函数CalcolateMaxAvg的返回。 我会像在c中那样使用Waitazure异步javascript后端-等待函数,javascript,azure,asynchronous,backend,azure-mobile-services,Javascript,Azure,Asynchronous,Backend,Azure Mobile Services,我正在使用Azure移动服务和javascript后端。我的问题是该函数不等待其他函数的结束 我试着选择一个有分词规则的词。我想选择item.wordnumber最高的项目。如果没有几个项目具有相同的item.wordnumber,我想在其他表中选择与该项目关联的投票数最高的人 此脚本不等待函数CalcolateMaxAvg的返回。 我会像在c中那样使用Wait var tableWords = tables.getTable('Word'); var tableVotes = tables.g
var tableWords = tables.getTable('Word');
var tableVotes = tables.getTable('Votes');
var avgVotesActualWord = 0;
var maxItem = null;
var maxItemVote = 0;
function WordChoice() {
var select = tableWords.orderByDescending('wordnumber').read({success:
function (results)
{
results.forEach(function(item)
{
if(maxItem == null)
{
maxItem = item;
maxItemVote = tableVotes.where({idword: item.id}).read({success: CalcolateMaxAvg});
}
else if(item.wordnumber > maxItem.wordnumber)
{
maxItem = item;
maxItemVote = tableVotes.where({idword: item.id}).read({success: CalcolateMaxAvg});
}
else if(item.wordnumber == maxItem.wordnumber)
{
//chack who have more votes
avgVotesActualWord = 0;
avgVotesActualWord = tableVotes.where({idword: item.id}).read({success: CalcolateMaxAvg});
//the problem is avgVoteActualWord that is always NaN
console.log('Word: %s with avg: %d', item.word, avgVotesActualWord);
if(avgVotesActualWord > maxItemVote)
{
//take the actualword because have more votes
maxItem = item;
maxItemVote = avgVotesActualWord;
}
}
})
if(maxItem != null)
{
console.log('parola: %s', maxItem.word);
maxItem.selected = true;
tableWords.update(maxItem);
}
else
{
console.log('null');
}
}
});
}
function CalcolateMaxAvg(resultsVote)
{
var sum = 0;
var count = 0;
var avg = 0;
resultsVote.forEach(function(itemVote)
{
sum = sum + itemVote.vote;
count = count + 1;
})
if(count > 0)
{
avg = sum / count;
}
//this is a correct value of avgVoteActualWord, but he don't wait the return of this value
console.log('avg: %d', avg);
return avg;
}
问题是对表的调用。其中…读取。。。是异步的-它不会返回CalcolateMaxAvg函数返回的数字,也不会返回任何内容。您需要重写代码以支持JavaScript的异步性,这与下面的代码大致相同
var tableWords = tables.getTable('Word');
var tableVotes = tables.getTable('Votes');
var avgVotesActualWord = 0;
var maxItem = null;
var maxItemVote = 0;
function WordChoice() {
var select = tableWords.orderByDescending('wordnumber').read({
success: function (results)
{
function processNextResult(index) {
if (index >= results.length) {
// All done
if(maxItem != null)
{
console.log('parola: %s', maxItem.word);
maxItem.selected = true;
tableWords.update(maxItem);
}
else
{
console.log('null');
}
return;
}
var item = results[index];
if (maxItem == null) {
maxItem = item;
tableVotes.where({ idword: item.id }).read({ success: simpleProcessVotesResult });
} else if (item.wordnumber > maxItem.wordnumber) {
maxItem = item;
tableVotes.where({ idword: item.id }).read({ success: simpleProcessVotesResult });
} else if (item.wordnumber == maxItem.wordnumber) {
//check who have more votes
avgVotesActualWord = 0;
tableVotes.where({idword: item.id}).read({
success: function(resultsVote) {
avgVotesActualWord = CalcolateMaxAvg(resultsVote);
//the problem is avgVoteActualWord that is always NaN
console.log('Word: %s with avg: %d', item.word, avgVotesActualWord);
if(avgVotesActualWord > maxItemVote)
{
//take the actualword because have more votes
maxItem = item;
maxItemVote = avgVotesActualWord;
}
processNextResult(index + 1);
}
});
} else {
processNextResult(intex + 1);
}
}
function simpleProcessVotesResult(resultsVote) {
maxItemsVote = CalcolateMaxAvg(resultsVote);
processNextResult(intex + 1);
}
processNextResult(0);
}
});
}
function CalcolateMaxAvg(resultsVote)
{
var sum = 0;
var count = 0;
var avg = 0;
resultsVote.forEach(function(itemVote)
{
sum = sum + itemVote.vote;
count = count + 1;
})
if(count > 0)
{
avg = sum / count;
}
//this is a correct value of avgVoteActualWord, but he don't wait the return of this value
console.log('avg: %d', avg);
return avg;
}