I am trying to map some items returned to me from a API using a class and constructor with javascript.
My question is what I am doing wrong, since the log before the mapping "Result before Map" logs out my array of items. But after my map I get nothing and everything in my constructor is undefined.
class Test {
constructor(obj) {
this.testValue = obj.testValue
}
}
async function getItems() {
const promises = []
const response = (await fetch(url)).json()
promises.push(response)
const result = await Promise.all(promises)
console.log('Result before Map:', result)
const tests = result.map(test => new Test(test))
console.log('Result after Map:', tests)
}
You have one too many "await"s in there.
async function getItems() {
const promises = []
promises.push(fetch(url));
const result = await Promise.all(promises)
.map((r) => r.json());
console.log('Result before Map:', result)
const tests = result.map((t) => new Test(t))
console.log('Result after Map:', tests)
}
The question is where "url" comes from. Currently there is no reference to url and even if, then it is just a single url. Maybe you're looking for something like:
async function getItems(urls) {
const promises = urls.map((u) => fetch(u));
const result = await Promise.all(promises)
.map((r) => r.json());
console.log('Result before Map:', result)
const tests = result.map((t) => new Test(t))
console.log('Result after Map:', tests)
}
With a single url, it would just be
async function getItem(url) {
const result = await fetch(url);
const resJSON = result.json()
console.log('Result before Map:', resJSON)
const test = new Test(resJSON);
console.log('Result after Map:', test)
}