I am ordering some items with their priorities. I used a loop for that. However, I get some weird outputs like [1,1,2,2,3] instead of [1,2,3,4,5](these are priorities btw). The loop is below.
const switchPriority = async function(catId, srcI, destI){
let indexofCat;
try {
for (let i = 0; i < data[0].length; i++) {
const element = data[0][i];
if(element.id === catId){
indexofCat = i;
}
}
let Item = Parse.Object.extend('Item')
let itemQuery = new Parse.Query(Item)
for (let i = (srcI>destI?destI:srcI); i < (srcI>destI?(srcI+1):(destI+1)); i++) {
let id = data[1][indexofCat][i].id;
let item = await itemQuery.get(id);
item.set("priority",i+1);
await item.save();
}
} catch (error) {
alert(error)
}
}
Why there is such a problem? When I add alert to the loop, with some delay it gives proper outputs. How can I solve this ? I am appreciate for your help.
I don't know if you forgot, but it's necessary use the word async like this await works. You can insert your code into a function:
async function parse(){
for (let i = (srcI); i < (destI); i++) {
// alert("index in loop "+ i);
let id = data[1][indexofCat][i].id;
let item = await itemQuery.get(id);
// alert(item.get("name"));
item.set("priority",i+1);
await item.save();
}
}
Look at for more details: https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Statements/async_function
You can also promisify a function that you needs to guarantee that it be executed before the next instruction. How?
function createPromise (parameter) {
return new Promise((resolve, reject) => {
resolve(console.log(parameter))
})
}
async function test(){
console.log('First')
await createPromise('Promise')
console.log('Second')
}
test()Look at: https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Global_Objects/Promise